Answer:
y_g(x) = C1*x^2 + C2*x^-2 + x^4 / 12
Step-by-step explanation:
Given:-
- The following second order ODE :
x^2y''+xy'-4y=x*(x+x^3)
Find:-
Find a particular solution of the nonhomogeneous equation
Solution:-
- First note that the ODE given is a Cauchy Euler ODE. The order of derivative of independent and dependent variables are similar. The general form of Cauchy Euler ODE is:
a*x^n y^(n) + b*x^n-1 y^(n-1) + c*x^n-2 y^(n-2) + ... + d*y = f(x)
- We will use the following Auxiliary Equation to find the complementary solutions - Solving Homogeneous part of ODE.
am*(m-1) + bm + c = 0
Where, a,b,c are constants such that:
x^2y'' + xy' - 4y = 0
a = 1 , b = 1 , c = -4
- Solve the Auxiliary equation for (m) as follows:
m*(m-1) + m - 4 = 0
m^2 - 4 = 0
m = +/- 2 ...... ( Real and distinct roots )
- The complementary solutions to the Real and distinct roots from Auxiliary Equation is:
yc(x) = y1(x) + y2(x)
yc(x) = C1*x^2 + C2*x^-2 .... ( Complementary Solution ).
- Now for the non-homogeneous part of ODE. The function f(x) is defined as:
f(x) = x*( x + x^3 ) = x^2 + x^4
- We see that (x^2) term is common to both f(x) and complementary solution yc(x). So when we develop a particular solution, we have to make sure that the solution is independent from complementary solution. If not we multiply the particular solution with (x^n). Where n is the smallest possible integer for which the solution is independent. So in our case ( Using undetermined Coefficient method ) :
y_p (x) = A*x^4 + B*x^3 + C*x^2 + D*x + E
- To make the solution independent we multiply y_p by (x^3) where n = 3.
y_p (x) = A*x^7 + B*x^6 + C*x^5 + D*x^4 + E*x^3
- Take first and second derivatives of the y_p(x) as follows:
y'_p(x) = 7A*x^6 + 6B*x^5 + 5C*x^4 + 4D*x^3 + 3E*x^2
y''_p(x) = 42Ax^5 + 30Bx^4 + 20Cx^3 + 12Dx^2 + 6Ex
- Substitute y_p(x) , y'_p(x) and y''_p(x) into the ODE given:
42Ax^7 + 30Bx^6 + 20Cx^5 + 12Dx^4 + 6Ex^3
+ 7Ax^7 + 6B*x^6 + 5C*x^5 + 4D*x^4 + 3E*x^3
- ( 4Ax^7 + 4B*x^6 + 4C*x^5 + 4D*x^4 + 4E*x^3 )
--------------------------------------------------------------------------------
45Ax^7 + 32Bx^6 + 21Cx^5 + 12Dx^4 + 5Ex^3
---------------------------------------------------------------------------------
45Ax^7 + 32Bx^6 + 21Cx^5 + 12Dx^4 + 5Ex^3 = x^2 + x^4
- Compare the coefficients:
A = B = C = E = 0
D = 1 / 12.
The particular solution is:
y_p(x) = x^4 / 12
- The general solution is as follows:
y_g(x) = yc(x) + y_p(x)
y_g(x) = C1*x^2 + C2*x^-2 + x^4 / 12
Answer:
The particular solution to the differential equation
x²y'' + xy' - 4y = x(x + x³)
is
y_p = (1/12)x^4 - x²/2 - x/3
Step-by-step explanation:
Given the differential equation:
x²y'' + xy' - 4y = x(x + x³)...............(1)
First, we solve the homogeneous part of (1)
x²y'' + xy' - 4y = 0...........................(2)
Let x = e^z
=>z = lnx
Let D = d/dz
dz/dx = (1/x)
dy/dx = (dy/dz).(dz/dx)
= (1/x)(dy/dz)
dy/dz = xdy/dx = xy' = Dy
d²y/dx² = (-1/x²)(dy/dz) + (1/x)(d²y/dx²)(dz/dx)
= (1/x²)(d²y/dx² - dy/dz) = (1/x²)(D² - D)y
Using these, (2) becomes
(D² - D)y + Dy - 4y = 0
(D² - 4)y = 0
The auxiliary equation is
m² - 4 = 0
(m - 2)(m + 2) = 0
m1 = 2, m2 = -2
The complementary function is
y = C1e^(2z) + C2e^(-2z)
But z = lnx
y_c = C1x² + C2/x² ...........................(3)
Now we solve (1) using the method of undetermined coefficients.
The nonhomogeneous part is
x(x + x³) = x² + x^4
So, we assume a particular solution of the form
y_p = Ax^4 + Bx³ + Cx² + Dx + E
y'_p = 4Ax³ + 3Bx² + 2Cx + D
y''_p = 12Ax² + 6Bx + 2C
Using these in (1)
x²y''_p + xy'_p - 4y_p = x²(12Ax² + 6Bx + 2C) + x(4Ax³ + 3Bx² + 2Cx + D) - 4(Ax^4 + Bx³ + Cx² + Dx + E)
= x² + x^4
12Ax^4 + 6Bx³ + 2Cx + 4Ax^4 + 3Bx³ + 2Cx² + Dx - 4Ax^4 - 4Bx³ - 4Cx² - 4Dx - 4E = x² + x^4
Comparing the coefficients of various powers of x, we have
12A + 4A - 4A = 1
12A = 1
=> A = 1/12
6B + 3B - 4B = 0
5B = 0
=> B = 0
2C - 4C = 1
-2C = 1
=> C = -1/2
2C + D - 4D = 0
2C - 3D = 0
2C = 3D
2(-1/2) = 3D
=> D = -1/3
-4E = 0
=> E = 0
(A, B, C, D, E) = (1/12, 0, -1/2, -1/3, 0)
y_p = Ax^4 + Bx³ + Cx² + Dx + E
= (1/12)x^4 - (1/2)x² - (1/3)x
The general solution is
y = y_c + y_p
= C1x² + C2/x² + (1/12)x^4 - x²/2 - x/3
The amount of corn chips dispensed into a bag by the dispensing machine has been identified as possessing a normal distribution with a mean of μ=48.5 ounces and a standard deviation of σ=0.2 ounce. What chip amount represents the 67th percentile, p 67, for the bag weight distribution? Round to the nearest hundredth. Hint: the 67th percentile of the standard normal curve is z=0.44. Round your answer to to decimal places.
The chip amount that represents the 67th percentile is 48.588.and this can be determined by using the formula of z-score.
Given :
The amount of corn chips dispensed into a bag by the dispensing machine has been identified as possessing a normal distribution with a mean of μ = 48.5 ounces and a standard deviation of σ = 0.2 ounces.
To determine the chip amount that represents the 67th percentile, the below formula can be used:
[tex]\rm z = \dfrac{x-\mu}{\sigma}[/tex]
Now, substitute the values of known terms in the above formula:
[tex]\rm 0.44 = \dfrac{x - 48.5}{0.2}[/tex]
Cross multiply in the above equation.
[tex]\rm 0.44\times 0.2 = x - 48.5[/tex]
Now further, simplify the above equation.
0.088 = x - 48.5
x = 48.5 + 0.088
x = 48.588
So, the chip amount that represents the 67th percentile is 48.588.
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The weight that represents the 67th percentile of the corn chip bags, with a given mean of 48.5 ounces and a standard deviation of 0.2 ounce, is 48.59 ounces, calculated using the z-score provided.
To determine the amount of corn chips that represents the 67th percentile, p67, for a bag's weight distribution with a mean of μ = 48.5 ounces and a standard deviation of σ = 0.2 ounce. Given that the z-score for the 67th percentile is z = 0.44, we can use the percentile to z-score formula to find the corresponding weight.
To convert a z-score to a specific value within a normal distribution, we use the formula:
X = μ + zσ
For the 67th percentile:
X = 48.5 + (0.44 × 0.2)
X = 48.5 + 0.088
X ≈ 48.59 ounces (rounded to two decimal places)
This means that the weight that represents the 67th percentile of corn chip bag weights, to the nearest hundredth, is 48.59 ounces.
Six people, named Anna, Bob, Chandra, Darlene, Ed, and Frank, will be interviewed for a job. The interviewer will choose two at random to interview on the first day. What is the probability that Darlene is interviewed first and Bob is interviewed second? Express your answer as a fraction or a decimal, rounded to four decimal places.
Answer:
there is a 1/18th percent chance Darlene and bob will go in that order
Step-by-step explanation:
A toy car launched into the air has a height (h feet) at any given time (t second) as h= -16t + 160t until it hits the ground. At what times is it at a height of 9 feet above the ground?
Answer:
[tex]t_{1} \approx 9.943\,s[/tex] and [tex]t_{2} \approx 0.057\,s[/tex]
Step-by-step explanation:
The following polynomial is needed to be solved:
[tex]-16\cdot t^{2} + 160\cdot t - 9 = 0[/tex]
The roots are found by means of the General Equation for Second-Order Polynomials:
[tex]t_{1} \approx 9.943\,s[/tex] and [tex]t_{2} \approx 0.057\,s[/tex]
Physically speaking, both solutions are reasonable.
Answer:
t = 0.0625
Step-by-step explanation:
Given that,
Height, h = -16t + 160t
To obtain time,t at height,h = 9feet
We substitute h = 9 into the given equation to have:
9 = - 16t + 160t
: 9 = 144t
t = 9/ 144 = 0.0625
A bakery uses 8 tablespoons of honey for every 10 cups of flour to make bread
dough. Some days they bake bigger batches and some days they bake smaller
batches, but they always use the same ratio of honey to flour.
Blank 1: How much flour is needed for 16 tablespoons of honey? Whole Number
Blank 2: How much flour is needed for 15 tablespoons of honey? Decimal or Fraction
Answer:
Blank 1: 20 cups of flour
Blank 2: 18.75 cups of flour or 18 3/4 cups of flour.
Step-by-step explanation:
Blank 1: It tells you for every 8 tablespoons of honey they need 10 cups of flour. 16 table spoons of honey is double the 8 tablespoons of honey so you would also double the amount of flour.
2 x 10= 20.
Blank 2: You can find out how much cups of flour is needed for one table spoon of honey by dividing the cups of flour by 8 which gives you 1 and 1/4 or 1.25. Then you can multiply that by 15 for the 15 tablespoons of honey.
1.25 x 15 = 18.75
1 1/4 x 15 = 75/4 or 18 3/4.
Using the given ratio of 8 tablespoons of honey to 10 cups of flour, 16 tablespoons of honey requires 20 cups of flour and 15 tablespoons of honey requires 18.75 cups of flour.
Explanation:The bakery's recipe uses a constant ratio of 8 tablespoons of honey to 10 cups of flour. To find how much flour is needed for different amounts of honey, we use this ratio as a guide.
For 16 tablespoons of honey (which is twice the original amount), we also double the amount of flour, which gives us 20 cups of flour (10 cups*2).
For 15 tablespoons of honey, the situation is not as straightforward and we need to establish a proportion. This requires us to set up the equation as follows: (8 tablespoons of honey : 10 cups of flour = 15 tablespoons of honey : X cups of flour). Solving for X, we get X = 18.75 cups of flour.
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A.(-3,0)
B.(1,0)
C.(-4,-1)
D.(-1,-4)
If the annual coupon rate is 7 percent on a $1000 face value bond with market price equal to $ 985. Find current yield
Answer:
7.1%
Step-by-step explanation:
Current yield is the ratio of coupon payment of a bond to its current market price. It is calculated by using coupon payment and the current market value of the bond.
As per given data
Coupon rate = 7%
Face value = $1,000
Market Value = $985
Coupon Payment = $1,000 x 7% = $70
Formula for Current yield is as follow
Current Yield = Annual Coupon Payment / Current Market Price
Current Yield = $70 / $985
Current Yield = 7.11%
jose began the day with 25 pieces of candy. after giving a number of pieces to peter, jose had 80% of his original amount. if he then gave 4 more pieces to haley, how many pieces of candy does jose have now?
Give a recursive definition of each of these sets of ordered pairs of positive integers. [Hint: Plot the points in the set in the plane and look for lines containing points in the set.] a) S = {(a, b) | a ∈ Z+ , b ∈ Z+ , and a + b is odd}
Answer:
(2,1), (1,2) is your base step
if (a,b) is in the set (a+1,b+1) will be in the set
if (a,b) is in the set (a+2,b) will be in the set
if (a,b) is in the set (a,b+2) will be in the set.
Step-by-step explanation:
Think about how to solve this problem in general. How can you assure that the sum a+b is odd ?
Think about this, what happens when you sum two even numbers ? The result is even or odd ?
2+6 = 8 (even )
10+12 = 22 (even)
And what happens when you sum two odd numbers ? The result will be even or odd ? Look
3+7 = 10 (even)
5+11 = 16 (even)
Therefore to assure that a+b is odd, one of them has to be odd and one of them has to be even, that is why
(2,1), (1,2) is your base step
if (a,b) is in the set (a+1,b+1) will be in the set
if (a,b) is in the set (a+2,b) will be in the set
if (a,b) is in the set (a,b+2) will be in the set.
The set of ordered pairs that are positive integers and have an odd sum can be defined recursively by starting with the set {(1,2)}, and then adding 2 to either a or b for every pair in the set to generate additional pairs that satisfy the conditions.
Explanation:The set of ordered pairs of positive integers S given by S = {(a, b) | a ∈ Z+ , b ∈ Z+ , and a + b is odd} can be defined recursively as follows: Start with S = {(1,2)}, which is the smallest possible set that satisfies the conditions. For every (a,b) in S, (a+2, b) and (a, b+2) are also in S, since adding 2 to either a or b results in a sum that is still odd (since an even number plus an odd number equals an odd number).
As a result, the set S of all ordered pairs that result from these operations will satisfy the conditions given, namely being positive integers and having an odd sum. This demonstrates a recursive method for defining the set of ordered pairs.
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Jon drives a total of 47 miles each day to take his children to and from school. The children go to school 5 days a week. Jon's vehicle gets 21 miles per gallon of gas. About how many gallons of gas does Jon need to take his children to and from school each week?
Answer:
The correct answer is that Jon needs approximately 11.19 gallons of gas to take his children to and from school each week.
Step-by-step explanation:
To solve this problem, we first need to figure out how many miles Jon drives per week. To do this, we need to multiply the number of miles Jon drives per day (47 miles) by the number of days Jon drives per week (5).
47 * 5 = 235
This means that Jon drives 235 miles per week. Now, to figure out how many gallons of gas Jon uses, we need to divide the number of miles Jon drives (235) by the number of miles per gallon Jon's vehicle gets (21).
235/21 = 11.19
Therefore, the answer is that Jon needs about 11 gallons of gas to take his children to and from school each week.
Hope this helps!
patricia is building the community dog park. she plans to build the dog park right beside the city park so she can use one side of the existing fence. her budget allows her yo purchase 340 feet of fencing. in order to make the area of the dog park as large as possible, determine the dimensions of the dog park if one side of the fence is attached to thr city park's fence
Answer:
85 feet by 170 feet
Step-by-step explanation:
Let the dimension of the dog park be x and y
Since only three sides will be fenced,
Perimeter, x+2y=340
x=340-2yArea of the Park, A(x,y)=xyOur goal is to determine the dimension of the park which maximizes the area.
Substituting x=340-2y into A(x,y)
[tex]A(y)=y(340-2y)\\A(y)=-2y^2+340y[/tex]
To maximize the area, we find the vertex using the equation of line of symmetry. Note that you can also find the critical points instead.
Equation of symmetry, [tex]y=-\dfrac{b}{2a}[/tex]
a=-2, b=340
[tex]y=-\dfrac{340}{2(-2)}=85[/tex]
Recall that: x=340-2y
x=340-2(85)=340-170=170 feet
Since x=170 feet, y=85 feet
The dimension of the park which maximizes the area are: 85 feet by 170 feet.
Furthermore, the part opposite the existing fence is 170 feet.
Final answer:
To maximize the area of the dog park with 340 feet of fencing using one existing fence side, an optimization problem is solved where the park's width and length are calculated. The area is maximized by setting the park length to be the longest along the existing fence and finding the width accordingly.
Explanation:
The question asks for the dimensions of the dog park Patricia can build with 340 feet of fencing and utilizing one side of the existing city park's fence to maximize the area. This is a problem of optimization that involves finding the maximum area of a rectangle given the perimeter. Since one side is already fenced, we only need to fence three sides. The perimeter P of three sides is 2w + l = 340 (where w is the width and l is the length we need to find and fencing for). To maximize the area, A = w * l, we use calculus or recognize this as a problem of a fixed perimeter rectangle, where the area is maximized when the rectangle is a square, i.e., the width equals the length.
However, since one side is already existing, Patricia can only maximize the area by setting 2w + l = 340, meaning the park would be longest along the existing fence. By rearranging, l = 340 - 2w, and substituting in the area formula, A = w(340 - 2w), we get a quadratic equation which represents a parabola that opens downwards, meaning its vertex represents the maximum point. Completing the square or using calculus to find the derivative and set it to zero will give us the optimal width, and thus, the optimal length to maximize area.
A survey reported that 5% of Americans are afraid of being alone in a house at night. If a random sample of 20 Americans is selected, what is the probability that exactly 3 people in the sample are afraid of being alone at night.
Final answer:
The probability that exactly 3 people out of a sample of 20 Americans are afraid of being alone in a house at night, given that 5% of Americans have this fear, is approximately 13.98%.
Explanation:
The question asks for the probability that exactly 3 people in a sample of 20 Americans are afraid of being alone in a house at night, given that 5% of Americans have this fear. This can be solved using the binomial probability formula, which is P(X = k) = C(n, k) * p^k * (1-p)^(n-k), where n is the number of trials, k is the number of successful trials, p is the probability of success on an individual trial, and C(n, k) is the number of combinations of n items taken k at a time.
Plugging in the values, we get P(X = 3) = C(20, 3) * 0.05³* 0.95¹⁷ First, calculate C(20, 3) = 20! / (3!(20-3)!) = 1140. Then calculate the probability: P(X = 3) = 1140 * 0.05³* 0.95¹⁷.
Doing the math, P(X = 3) ≈ 0.1398, or approximately 13.98%.
Final answer:
The probability that exactly 3 out of 20 Americans are afraid of being alone at night is found by using the binomial probability formula, which incorporates the number of people in the sample, the number who are afraid, and the overall chance of fear of being alone at night.
Explanation:
To find the probability that exactly 3 people out of a random sample of 20 Americans are afraid of being alone at night when it is known that 5% of Americans have this fear, we can use the binomial probability formula:
P(X = k) = C(n, k) * p^k * (1-p)^(n-k)
Where:
n is the number of trials (in this case, 20)
k is the number of successes (in this case, 3)
p is the probability of success on an individual trial (5% or 0.05)
C(n, k) is the number of combinations of n things taken k at a time
Let's calculate:
Compute C(20, 3): This is 20! / (3! * (20-3)!).
Calculate p^k, which is 0.05^3.
Calculate (1-p)^(n-k), which is (1-0.05)^(20-3).
Multiply these together to get the probability.
After performing the calculations, we determine the probability of exactly 3 out of 20 Americans being afraid of being alone at night.
what is the value of z?
If the explicit formula for a sequence is 1/n, what is the second term
of the sequence, expressed as a fraction?
Answer:
1/2
Step-by-step explanation:
Put the term number in the formula to get your answer.
Term 2 = 1/2
Substituting n with 2 into the explicit sequence formula 1/n gives the second term of the sequence as 0.5 which expressed as a fraction is 1/2.
Explanation:The explicit formula given in the question is 1/n, where 'n' represents the term number in the sequence.
When we want to find out the second term of the sequence, we substitute n with 2 into the formula.
So the calculation is 1/2 = 0.5.
Expressing 0.5 as a fraction, you get 1/2.
Therefore, the second term of the sequence, expressed as a fraction, is 1/2.
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A face of a solid is
Answer:
In solid geometry, a face is a flat (planar) surface that forms part of the boundary of a solid object; a three-dimensional solid bounded exclusively by faces is a polyhedron. (OR) A face is a 2D shape that makes up one surface of a 3D shape, an edge is where two faces meet and a vertex is the point or corner of a geometric shape.
Step-by-step explanation:
A very large study showed that aspirin reduced the rate of first heart attacks by 44%. A pharmaceutical company thinks they have a drug that will be more effective than aspirin, and plans to do a randomized clinical trial to test the new drug. a) What is the null hypothesis the company will use? b) What is their alternative hypothesis?c) Is this question dealing with 1 mean or 1 proportion
Answer:
a) Null hypothesis: [tex]p \leq 0.44[/tex]
b) Alternative hypothesis: [tex]p > 0.44[/tex]
c) For this case our parameter of interest is a proportion "reduced rate of first heart attacks for a new drug". for this reason the answer would be 1 proportion and we can conduct the hypothesis with a 1 z proportion test
Step-by-step explanation:
For this case the pharmaceutical company thinks they have a drug that will be more effective than aspirin and on this case that means a better rate in order to reduce the heart attacks (that represent the alternative hypothesis since that;s what they want to proof), and the complement would be the null hypothesis.
Part a
Null hypothesis: [tex]p \leq 0.44[/tex]
Part b
Alternative hypothesis: [tex]p > 0.44[/tex]
Part c
For this case our parameter of interest is a proportion "reduced rate of first heart attacks for a new drug". for this reason the answer would be 1 proportion and we can conduct the hypothesis with a 1 z proportion test
Customers at TAB are charged for the amount of salad the take. Sampling suggests that the
amount of salad taken is uniformly distributed between 5 ounces and 15 ounces. Let
Χ = Salad plate filling weight.
i. Find the probability density function of Χ
Answer:
The probability density function of X is:
[tex]f_{X}(x)=\frac{1}{15-5}=\frac{1}{10};\ 5<X<15[/tex]
Step-by-step explanation:
A continuous Uniform distribution is the probability distribution of a random outcome of an experiment that lies with certain specific bounds.
Consider that random variable X follows a continuous Uniform distribution and the value of X lies between a and b.
The probability density function of the random variable X is:
[tex]f_{X}(x)=\frac{1}{b-a};\ a<X<b,\ a<b[/tex]
Now, in this case it is provided that the amount of salad taken is uniformly distributed between 5 ounces and 15 ounces.
The random variable X is defined as:
Χ = Salad plate filling weight.
The probability density function of the salad plate filling weight is:
[tex]f_{X}(x)=\frac{1}{15-5}=\frac{1}{10};\ 5<X<15[/tex]
In mathematics at a college level, this answer explains how to find the probability density function of a uniformly distributed random variable representing the amount of salad taken by customers at TAB.
Given: Customers at TAB take salad that is uniformly distributed between 5 ounces and 15 ounces. Let X = Salad plate filling weight.
i. Find the probability density function of X: Since the salad amount is uniformly distributed, the probability density function is a horizontal line, given by f(x) = 1/(b-a), where a = 5 and b = 15, so f(x) = 1/10 for 5 ≤ x ≤ 15.
A company is developing a new high-performance wax for cross country ski racing. In order to justify the price marketing wants, the wax needs to be very fast. Specifically, the mean time to finish their standard test course should be less than 55 seconds for a former Olympic champion. To test it, the champion will ski the course 8 times. The champion's time (selected at random) 57.9, 62.9, 50.6, 50.5, 48.2, 47.2, 50.2, and 43.1 seconds to complete the test course.1. Should they market the wax? Assume the assumptions and conditions for appropriate hypothesis testing are met for the sample. Assume (Sig=0.05). what is the null and alternative hypothesis? Choose the correct answer below.A) H0: u=55 vs. HA: u>55B) H0: u>55 vs. HA: u=55C) H0: u<55 vs. HA: u=55D) H0: u=55 vs. HA: u<552.What is the value of the test statistic?
A)Yes they should market the wax because it thaws before 55 seconds
C) Null hypothesis: mean <55 vs Alternative =55
D) The value is 51.33 moments
What is Hypothesis?
When The selected samples for the champion are: 57.9, 62.9, 50.6, 50.5,48.2,47.2,50.2 and 43.1
The mean is ;
Then, Sum =57.9 + 62.9 + 50.6 + 50.5+48.2+47.2+50.2+ 43.1 =410.6
After that, Mean is = 410.6/8 =51.33= mean
Considering Significant is =0.05, therefore, applying this level will give you 51.28-51.38
if particularly, the meantime to complete their standard test course should be less than 55 seconds for a former Olympic champion, then the nullified hypothesis is correct
After that; Null hypothesis: mean <55
Hence, Alternative hypothesis: mean =55
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The function R(x)equals108 StartRoot x EndRoot gives the total revenue per year in thousands of dollars generated by a small business having x employees. Use this function to evaluate R(12)minusR(11). If the salary for the twelfth employee is $ 26 comma 000, is it a good decision to hire the twelfth employee?
Answer:
Step-by-step explanation:
We are given that [tex] R(x) = 108\sqrt[]{x}[/tex] is the revenue for having x employees.
Let us calculate the following
[tex]R(12)-R(11) = 108\sqrt[]{12}-108\sqrt[]{11} = 15.93[/tex] REcall that is amount represents the revenue that having one extra employee would have.
We have that the salary of the 12th employee would be 26000. One criteria to define if it's a good idea to hire the 12th employee is to check if the profit for having an extra employee is positive. We will take the revenue of the extra employee minus the cost and check if it is positiv. Then,
[tex](108\sqrt[]{12}-108\sqrt[]{11})\text{(revenue for 12 employees)}-26000\text{(cost for the 12th employee} =-25984<0[/tex]
Since it is a negative amount, this means that it would be more expensive to have one extra employee than the revenue it would generate. Therefore, it won't be suitable to hire the 12th employee
The school auditorium has 34
rows of seats. The first row has
12 seats, the second row has 14
seats, and the third row has 16
seats. If this pattern continues,
how many chairs will be
in the last row?
Step-by-step explanation:
Total no of rows = 34
No of seats in first row = 12
No of seats in second row = 14
Third row = 16
If we continue this pattern of even numbers the last row will have 78 seats
In 2001, there were about 62.5 thousand golden retrievers registered in the United States. In 2002, the number was 56.1 thousand. 28. Write a linear equation to predict the number of golden retrievers G that will be registered in year t.
To predict the number of golden retrievers G that will be registered in year t, use the linear equation G = -6.4t + 12868.9.
Explanation:To predict the number of golden retrievers G that will be registered in year t, we can use a linear equation. We have two data points: (2001, 62.5) and (2002, 56.1). We can use the slope-intercept form of a linear equation, y = mx + b, where m is the slope and b is the y-intercept.
Step 1: Determine the slope (m) using the formula m = (y2 - y1) / (x2 - x1) = (56.1 - 62.5) / (2002 - 2001) = -6.4
Step 2: Choose one of the data points and substitute the values into the equation to solve for b. Using (2001, 62.5), we can substitute x = 2001 and y = 62.5.
62.5 = -6.4 * 2001 + b
62.5 = -12806.4 + b
b = 12868.9
Step 3: The linear equation to predict the number of golden retrievers G is G = -6.4t + 12868.9.
The Institute of Education Sciences measures the high school dropout rate as the percentage of 16- through 24-year-olds who are not enrolled in school and have not earned a high school credential. In 2009, the high school dropout rate was 8.1%. A polling company recently took a survey of 1000 people between the ages of 16 and 24 and found 6.5% of them are high school dropouts. The polling company would like to determine whether the proportion of dropouts has changed from the historical value of 0.081. Use the 5% significance level. Set up the null and alternative hypotheses, calculate the Test Statistic, p-value, and write your conclusion in a sentence
Answer:
We conclude that the proportion of dropouts has changed from the historical value of 0.081.
Step-by-step explanation:
We are given that in 2009, the high school dropout rate was 8.1%. A polling company recently took a survey of 1000 people between the ages of 16 and 24 and found 6.5% of them are high school dropouts.
The polling company would like to determine whether the proportion of dropouts has changed from the historical value of 0.081.
Let p = proportion of school dropouts rate
SO, Null Hypothesis, [tex]H_0[/tex] : p = 0.081 {means that the proportion of dropouts has not changed from the historical value of 0.081}
Alternate Hypothesis, [tex]H_A[/tex] : p [tex]\neq[/tex] 0.081 {means that the proportion of dropouts has changed from the historical value of 0.081}
The test statistics that will be used here is One-sample z proportion statistics;
T.S. = [tex]\frac{\hat p-p}{{\sqrt{\frac{\hat p(1-\hat p)}{n} } } } }[/tex] ~ N(0,1)
where, [tex]\hat p[/tex] = sample proportion of high school dropout rate = 6.5%
n = sample of people = 1000
So, test statistics = [tex]\frac{0.065-0.081}{{\sqrt{\frac{0.065(1-0.065)}{1000} } } } }[/tex]
= -2.05
Also, P-value is given by the following formula;
P-value = P(Z < -2.05) = 1 - P(Z [tex]\leq[/tex] 2.05)
= 1 - 0.97982 = 0.0202 or 2.02%
Now at 5% significance level, the z table gives critical values between -1.96 and 1.96 for two-tailed test. Since our test statistics does not lies within the range of critical values of z so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region.
Therefore, we conclude that the proportion of dropouts has changed from the historical value of 0.081.
At a 5% significance level, the survey's dropout rate of 6.5% does not significantly differ from the historical rate of 8.1%, based on the calculated test statistic and p-value.
To determine whether the proportion of dropouts has changed from the historical rate of 0.081, we set up hypotheses:
Null Hypothesis (H0): The dropout rate in the survey (p) equals the historical rate (0.081).
Alternative Hypothesis (Ha): The dropout rate in the survey (p) is not equal to the historical rate (0.081).
Using a z-test for proportions, we calculate the test statistic:
Z = (0.065 - 0.081) / sqrt((0.081 * (1 - 0.081)) / 1000) ≈ -1.81
Next, we find the p-value associated with Z, which is approximately 0.0708.
Since 0.0708 > 0.05 (the significance level), we fail to reject the null hypothesis.
Conclusion: At the 5% significance level, there's insufficient evidence to suggest that the dropout rate in the survey differs from the historical rate of 0.081.
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Electric charge is distributed over the disk x2 + y2 ≤ 16 so that the charge density at (x, y) is rho(x, y) = 2x + 2y + 2x2 + 2y2 (measured in coulombs per square meter). Find the total charge on the disk.
Answer:
Required total charge is [tex]256\pi[/tex] coulombs per square meter.
Step-by-step explanation:
Given electric charge is dristributed over the disk,
[tex]x^2=y^2\leq 16[/tex] so that the charge density at (x,y) is,
[tex]\rho (x,y)=2x+2y+2x^2+2y^2[/tex]
To find total charge on the disk let Q be the total charge and [tex]x=r\cos\theta,y=r\sin\theta[/tex] so that,
[tex]Q={\int\int}_Q\rho(x,y) dA[/tex] where A is the surface of disk.
[tex]=\int_{0}^{2\pi}\int_{0}^{4}(2x+2y+2x^2+2y^2)dA[/tex]
[tex]=\int_{0}^{2\pi}\int_{0}^{4}(2r\cos\theta+2r\sin\theta+2r^2 \cos^{2}\theta+2r^2\sin^2\theta)rdrd\theta[/tex]
[tex]=2\int_{0}^{2\pi}\int_{0}^{4}r^2(\cos\theta+\sin\theta)drd\theta+2\int_{0}^{2\pi}\int_{0}^{4}r^3drd\theta[/tex]
[tex]=\frac{2}{3}\int_{0}^{2\pi}(\sin\theta+\cos\theta)\Big[r^3\Big]_{0}^{4}d\theta+2\int_{0}^{2\pi}\Big[\frac{r^4}{4}\Big]d\theta[/tex]
[tex]=\frac{128}{3}\int_{0}^{2\pi}(\sin\theta+\cos\theta)d\theta+128\int_{0}^{2\pi}d\theta[/tex]
[tex]=\frac{128}{3}\Big[\sin\theta-\cos\theta\Big]_{0}^{2\pi}+128\times 2\pi[/tex]
[tex]=\frac{128}{3}\Big[\sin 2\pi-\cos 2\pi-\sin 0+\cos 0\Big]+256\pi[/tex]
[tex]=256\pi[/tex]
Hence total charge is [tex]256\pi[/tex] coulombs per square meter.
To find the total charge on a disk with a given charge density, we need to integrate the charge density over the entire area of the disk. In this case, the charge density is not constant, so we convert the cartesian coordinates to polar coordinates which simplifies the integral. The final solution is obtained by performing a double integral over r and θ.
Explanation:The student is asking for the total electric charge on a disk with a given charge density. The disk being referred to is defined by the equation x² + y² ≤ 16, i.e., a disk of radius 4 units, and the charge density at any point (x, y) on the disk is given by rho(x, y) = 2x + 2y + 2x² + 2y².
In such problems, we find the total charge by integrating the charge density over the entire area of the disk. But in this case, we first need to convert the cartesian coordinates (x, y) to polar coordinates. which simplifies the integral. In polar coordinates, the area element is r dr dθ and the charge density funciton becomes rho(r, θ) = 2r cosθ + 2r sinθ + 2r². We perform a double integral of this function over r from 0 to 4 and θ from 0 to 2π.
This is a classic example of a problem in electrostatics, particularly involving the calculation of electric charge given a non-uniform charge density.
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B. There are 7 red, 8 green, and 6 blue marbles in the bag. Kate is going to
select two marbles at random, replacing each marble after she selects it.
What is the probability, in simplest form, that she will select a green and
then a blue marble? Please show your work.
[4 points]
Answer:
Probability of event
0.34
Step-by-step explanation:
A publisher reports that 45% of their readers own a laptop. A marketing executive wants to test the claim that the percentage is actually different from the reported percentage. A random sample of 370 found that 40% of the readers owned a laptop. determine the p-value of the test statistic
Answer:
[tex]z=\frac{0.40 -0.45}{\sqrt{\frac{0.45(1-0.45)}{370}}}=-1.933[/tex]
[tex]p_v =2*P(z<-1.933)=0.0532[/tex]
Step-by-step explanation:
Information given
n=370 represent the sample selected
[tex]\hat p=0.4[/tex] estimated proportion of readers owned a laptop
[tex]p_o=0.45[/tex] is the value that we want to test
z would represent the statistic
[tex]p_v[/tex] represent the p value
Creating the hypothesis
We need to conduct a hypothesis in order to test if the true proportion of readers owned a laptop is different from 0.45, the system of hypothesis are:
Null hypothesis:[tex]p=0.45[/tex]
Alternative hypothesis:[tex]p \neq 0.45[/tex]
The statistic is:
[tex]z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}[/tex] (1)
Replacing we got:
[tex]z=\frac{0.40 -0.45}{\sqrt{\frac{0.45(1-0.45)}{370}}}=-1.933[/tex]
Calculating the p value
We have a bilateral test so then the p value would be:
[tex]p_v =2*P(z<-1.933)=0.0532[/tex]
Gun rights vs. gun control: In a December 2014 report, "For the first time in more than two decades of Pew Research Center surveys, there is more support for gun rights than gun control." According to a Pew Research survey, 52% of Americans say that protecting gun rights is more important than controlling gun ownership. Gun control advocates in an urban city believe that the percentage is lower among city residents and conduct a survey. They test the hypotheses H0: p=0.52 versus Ha: p<0.52. They calculate a Pâvalue of 0.078.
Using a significance level of 0.05, which of the following is the best explanation for how to use the Pâvalue to reach a conclusion in this case? G
A. Since the Pâvalue is greater than the significance level, we reject the null hypothesis
B. Since the Pâvalue is greater than the significance level, we fail to reject the null hypothesis
C. Since the Pâvalue is greater than the significance level, we accept the null hypothesis.
Answer:
B. Since P-value is greater than the significance level, we fail to reject the null hypothesis
Explanation:
Given Significance Level is 0.05 and the P-Value is 0.078
Since P-value greater than the significance level the best explanation is given by
Option B i.e.,
Since P-value is greater than the significance level, we fail to reject the null hypothesis
The amount of Jen's monthly phone bill is normally distributed with a mean of $59 and a standard deviation of $10. What percentage of her phone bills are between $29 and $89?
Answer:
[tex]P(29<X<89)=P(\frac{29-\mu}{\sigma}<\frac{X-\mu}{\sigma}<\frac{89-\mu}{\sigma})=P(\frac{29-59}{10}<Z<\frac{89-59}{10})=P(-3<z<3)[/tex]
And we can find this probability with this difference:
[tex]P(-3<z<3)=P(z<3)-P(z<-3)[/tex]
And in order to find these probabilities using the normal standard distribution or excel and we got.
[tex]P(-3<z<3)=P(z<3)-P(z<-3)=0.9987-0.00135=0.99735[/tex]
So we expect about 99.735% of values between $29 and $89
Step-by-step explanation:
Let X the random variable that represent the amount of Jens monthly phone of a population, and for this case we know the distribution for X is given by:
[tex]X \sim N(59,10)[/tex]
Where [tex]\mu=59[/tex] and [tex]\sigma=10[/tex]
We are interested on this probability first in order to find a %
[tex]P(29<X<89)[/tex]
The z score is given by:
[tex]z=\frac{x-\mu}{\sigma}[/tex]
If we apply this formula to our probability we got this:
[tex]P(29<X<89)=P(\frac{29-\mu}{\sigma}<\frac{X-\mu}{\sigma}<\frac{89-\mu}{\sigma})=P(\frac{29-59}{10}<Z<\frac{89-59}{10})=P(-3<z<3)[/tex]
And we can find this probability with this difference:
[tex]P(-3<z<3)=P(z<3)-P(z<-3)[/tex]
And in order to find these probabilities using the normal standard distribution or excel and we got.
[tex]P(-3<z<3)=P(z<3)-P(z<-3)=0.9987-0.00135=0.99735[/tex]
So we expect about 99.735% of values between $29 and $89
Approximately 99.7% of Jen's phone bills are between $29 and $89, as this range lies within three standard deviations from the mean on a normally distributed curve with mean $59 and standard deviation $10.
To determine the percentage of Jen's phone bills that are between $29 and $89, we must calculate the z-scores for each value and then use the standard normal distribution to find the corresponding percentages.
The z-score is given by the formula:
Z = (X - μ)/σ
Where:
Z is the z-score,
X is the value in question,
μ is the mean,
σ is the standard deviation.
For X = $29:
Z = (29 - 59)/10
Z = -3
For X = $89:
Z = (89 - 59)/10
Z = 3
Using the standard normal distribution table or a calculator, we find that the probability of a z-score being between -3 and 3 is approximately 99.7%. Therefore, about 99.7% of Jen's phone bills fall between $29 and $89.
Thrush us a landscape architect. For his first public project he is asked a small scale drawing of a garden to be placed in the corner of a city park. The garden is a right triangle with base 10m and height 15m.
Answer:
Therefore, on the graph;
The height = 7.5 units
And base = 5.0 units
Attached is an image for further information;
Step-by-step explanation:
Given that;
1 unit on the grid represent 2m of the garden;
Ratio = 1/2 unit/m
For the height;
height h = 15m
On the graph;
h = 15m × 1/2 unit/m
h = 7.5 units
For the base;
Base b = 10m
On the graph;
b = 10m × 1/2 unit/m
b = 5 units
Therefore, on the graph;
The height = 7.5 units
And base = 5.0 units
A random sample of 42 college graduates who worked during their program revealed that a student spent an average 5.5 years on the job before being promoted. The sample standard deviation was 1.1 years. Using the 0.99 degree of confidence, what is the confidence interval for the population mean?
a. 5.04 and 5.96b. 5.06 and 5.94c. 2.67 and 8.33d. 4.40 and 6.60
Answer:
[tex]5.5-2.701\frac{1.1}{\sqrt{42}}=5.04[/tex]
[tex]5.5+2.701\frac{1.1}{\sqrt{42}}=5.96[/tex]
So on this case the 99% confidence interval would be given by (5.04;5.96)
And the best option would be:
a. 5.04 and 5.96
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
[tex]\bar X=5.5[/tex] represent the sample mean for the sample
[tex]\mu[/tex] population mean (variable of interest)
s=1.1 represent the sample standard deviation
n=42 represent the sample size
Solution to the problem
The confidence interval for the mean is given by the following formula:
[tex]\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}[/tex] (1)
In order to calculate the critical value [tex]t_{\alpha/2}[/tex] we need to find first the degrees of freedom, given by:
[tex]df=n-1=42-1=41[/tex]
Since the Confidence is 0.99 or 99%, the value of [tex]\alpha=0.01[/tex] and [tex]\alpha/2 =0.005[/tex], and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,41)".And we see that [tex]t_{\alpha/2}=2.701[/tex]
Now we have everything in order to replace into formula (1):
[tex]5.5-2.701\frac{1.1}{\sqrt{42}}=5.04[/tex]
[tex]5.5+2.701\frac{1.1}{\sqrt{42}}=5.96[/tex]
So on this case the 99% confidence interval would be given by (5.04;5.96)
And the best option would be:
a. 5.04 and 5.96
A rectangle has a height of 7 and a width of 2x^2-3 express the area of the entire rectangle
Find the area of the triangle 10cm 15 cm
Answer:
75 cm (if b=10 and h=15)
Step-by-step explanation:
The formula to calculate the area of a triangle is bh1/2. So you must do (10)(15)1/2, 10 multiplied by 15 equals 150. And 150 multiplied by 1/2 equals 75. Hope this helped!