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3 years ago

Evaluate the expression using an appropriate double angle formula.. cos^2(15) - sin^2(15)

Mathematics

1 answer:

riadik2000 [5.3K]3 years ago

7 0

Cos²(15°) - sin²(15°) = cos(15° * 2) = √(3/2 so this is the answer by using apropriate formula double angle identity

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Calculating the degrees of freedom, the sample variance, and the estimated standard error for evaluations using the t statistic

Yuliya22 [10]

Answer:

a) For the first part we have a sample of n =10 and we want to find the degrees of freedom, and we can use the following formula:

$df = n-1= 10-1=9$

d.9

b) $s^2 = \frac{SS}{n-1}= \frac{600}{41-1}= 15$

a.15

c) For this case we have the sample size n = 25 and the sample variance is $s^2 =400$ , the standard error can founded with this formula:

$SE = \frac{s^2}{\sqrt{n}}= \frac{400}{\sqrt{25}}= 80$

Step-by-step explanation:

Part a

For the first part we have a sample of n =10 and we want to find the degrees of freedom, and we can use the following formula:

$df = n-1= 10-1=9$

d.9

Part b

From a sample we know that n=41 and SS= 600, where SS represent the sum of quares given by:

$SS = \sum_{i=1}^n (X_i -\bar X)^2$

And the sample variance for this case can be calculated from this formula:

$s^2 = \frac{SS}{n-1}= \frac{600}{41-1}= 15$

a.15

Part c

For this case we have the sample size n = 25 and the sample variance is $s^2 =400$ , the standard error can founded with this formula:

$SE = \frac{s^2}{\sqrt{n}}= \frac{400}{\sqrt{25}}= 80$

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3 years ago

Exercise 8.12 introduces data on the average monthly temperature during the month babies rst try to crawl (about 6 months after

Afina-wow [57]

Answer:

The point has a high leverage

Step-by-step explanation:

The point has a high leverage as it would act as an infinitesimal point that will have a very huge/drastic impact on the fit of the model, and this impact can be seen in such ways as listed below :

Smaller coefficient of determination
Higher sum of squares error

removing this point will eliminate these drastic impact and make the correlation to be better.

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3 years ago

Find the sum of 9, eight times a number y and five times

MatroZZZ [7]

Step-by-step explanation:

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2 years ago

Help me Guess just help please

Andrew [12]

Answer:

maybe 2 only?

Step-by-step explanation:

I'm just guessing but it sounds right

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3 years ago

Read 2 more answers

What would the answer be???

Korolek [52]

Answer:

The solution is obtained by adding the two equations.

The solution is: (x, y) = ( $- \frac{2}{3}$ , $- \frac{7}{3}$ )

Step-by-step explanation:

We are given two equations with two variables. The strategy is to eliminate one variable and solve for both the variables.

The two equations are:

$7x + y = - 7 \hspace{15mm} \hdots (1)$

$2x - y = 1 \hspace{15mm} \hdots (2)$

Adding both the equations, we get:

$7x + 2x + y - y = - 7 + 1$

$\implies 9x = - 6$

$\implies x = - \frac{2}{3}$

Substituting the value of 'x', we get the value of y.

We substitute in (2). [Can be substituted in any equation].

We get: y = 2x - 1

$\imples y = 2\bigg(\frac{-2}{3}\bigg) - 1$

$\implies -\frac{4}{3} - 1$

$\implies y = -\frac{7}{3}$

So, we get the corresponding values of x and y which is the solution of the two equations.

4 0

3 years ago