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astra-53 [7]
3 years ago
10

3. Solve each of the following constant coefficient ordinary differential equations: (10 pts] a) y"+ 3y'- 28y = 0

Mathematics
1 answer:
eduard3 years ago
6 0

Answer:

y(t) = C_1e^{4t} + C_2e^{-7t}

Step-by-step explanation:

We are given the following information in the question:

y''+3y'-28y = 0

This can be written as:

(D^2 + 3D - 28)y = 0

The auxiliary equation obtained is:

m^2+ 3m - 28 = 0\\ m^2 + 7m - 4m - 28 = 0\\m(m+7)-4(m+7)=0\\(m-4)(m+7)\\m = 4, m = -7

Thus, the general solution of the equation is:

y(t) = C_1e^{4t} + C_2e^{-7t}\\\text{where } C_1, C_2 \text{ are constants}

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find rodrigos percent increase or decrease in sales each week. week 1, is 17 wwek 2, is 25 week 3, is 18 and week 4, is 27. his
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eu (european union) countries report that 46% of their labor force is female. The United Nations wnats to determine if the perce
Brrunno [24]

Answer:

Step-by-step explanation:

The question is incomplete. The complete question is:

EU (European Union) countries report that 46% of their labor force is female. The United Nations wants to determine if the percentage of females in the U.S. labor force is the same. Based on a sample of 500 employment records, representatives from the United States Department of Labor found that the 95% confidence interval for the proportion of females in the U.S. labor force is 0.357 to 0.443. If the Department of Labor wishes to tighten its interval, they should:

A. increase the confidence level

B. decrease the sample size

C. increase the sample size

D. Both A and B

E. Both A and C

Solution:

Confidence interval for population proportion is written as

Sample proportion ± margin of error

Where sample proportion is the point estimate for the population proportion.

Margin of error = z × √pq/n

The z score for 95% confidence level is 1.96

p = 46/100 = 0.46

q = 1 - p = 1 - 0.46

q = 0.54

n = 500

Margin of error = 1.96√0.46 × 0.54/500 = 0.044

To tighten it's interval, the margin of error needs to be reduced.

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Then

Margin of error = 2.58√0.46 × 0.54/500 = 0.058

It increased

Also, If we increase the sample size, say to 700, then

Margin of error = 1.96√0.46 × 0.54/700 = 0.037

It has reduced

Therefore, the correct options is

C. increase the sample size

8 0
3 years ago
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