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3 years ago

Verify the identity. sin (x+pi/2)=cos x

1 answer:

4 0

Given data
sin (x+pi/2)=cos x
now using sin law
sin(a+b)=sin(a)cos(b)+cos(a)sin(b)
now using above values
sin(pi/2+x)=sin(pi/2)cos(x)+cos(pi/2)sin(x)
as we know that
sin(pi/2)=1
cos(pi/2)=0
now putting these values
sin(pi/2+x)=1*cosx+0*1
sin(pi/2+x)=cosx
hence proved that

sin (x+pi/2)=cos x

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The number of electoral votes each state is assigned is determined by the size of its population every ten years. The chart show

sattari [20]

Answer:

D. $Q_3=47$

Step-by-step explanation:

We have been given a table that represents the the number of electoral votes California was assigned each decade of the past century. We are asked to find the 3rd quartile of our given data.

The number of votes are: 9, 13, 13, 22, 25, 32, 40, 45, 47, 54, 55.

We will use upper quartile formula to solve our given problem.

$Q_3=\frac{3}{4}*(n+1)^{\text{th term}}$ , where, n represents the number of elements in the data set.

We can see that our data set has 11 data points, so upon substituting n=11 in above formula we will get,

$Q_3=\frac{3}{4}*(11+1)^{\text{th term}}$

$Q_3=\frac{3}{4}*(12)^{\text{th term}}$

$Q_3=3*3^{\text{th term}}$

$Q_3=9^{\text{th term}}$

Now let us count 9th term of our data set. Upon counting our data set from left to right we can see that 9th term of our data set is 47, therefore, 3rd quartile of our given data is 47 and option D is the correct choice.

3 0

4 years ago

Read 2 more answers

The length of the line segment AB equals 3x+1 BC equals 4x-5 AC equals 8x-9

yanalaym [24]

Answer:

X = 5

Step-by-step explanation:

Here is what I am picturing (not to scale)

A ----------------B-----------C

We are given the information of AB (which equals 3x + 1), BC (which equals 4x - 5), and AC (which equals 8x - 9).

With reference to the line, AB + BC = AC

So,

3x + 1 + 4x - 5 = 8x - 9

7x - 4 = 8x - 9

5 = x

4 0

3 years ago

Two machines are used for filling plastic bottles to a net volume of 16.0 ounces. A member of the quality engineering staff susp

aleksandrvk [35]

Answer:

Step-by-step explanation:

Hello!

The objective is to test if the two machines are filling the bottles with a net volume of 16.0 ounces or if at least one of them is different.

The parameter of interest is μ₁ - μ₂, if both machines are filling the same net volume this difference will be zero, if not it will be different.

You have one sample of ten bottles filled by each machine and the net volume of the bottles are measured, determining two variables of interest:

Sample 1 - Machine 1

X₁: Net volume of a plastic bottle filled by the machine 1.

n₁= 10

X[bar]₁= 16.02

S₁= 0.03

Sample 2 - Machine 2

X₂: Net volume of a plastic bottle filled by the machine 2

n₂= 10

X[bar]₂= 16.01

S₂= 0.03

With p-values 0.4209 (for X₁) and 0.6174 (for X₂) for the normality test and using α: 0.05, we can say that both variables of interest have a normal distribution:

X₁~N(μ₁;δ₁²)

X₂~N(μ₂;δ₂²)

Both population variances are unknown you have to conduct a homogeneity of variances test to see if they are equal (if they are you can conduct a pooled t-test) or different (if the variances are different you have to use the Welche's t-test)

H₀: δ₁²/δ₂²=1

H₁: δ₁²/δ₂²≠1

α: 0.05

$F= \frac{S^2_1}{S^2_2} * \frac{Sigma^2_1}{Sigma^2_2} ~~F_{n_1-1;n_2-1}$

Using a statistic software I've calculated the test

$F_{H_0}= 1.41$

p-value 0.6168

The p-value is greater than the significance level, so the decision is to not reject the null hypothesis then you can conclude that both population variances for the net volume filled in the plastic bottles by machines 1 and 2 are equal.

To study the difference between the population means you can use

$t= \frac{(X[bar]_1-X[bar]_2)-(Mu_1-Mu_2}{Sa\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } } ~~t_{n_1+n_2-2}$

The hypotheses of interest are:

H₀: μ₁ - μ₂ = 0

H₁: μ₁ - μ₂ ≠ 0

α: 0.05

$Sa= \sqrt{\frac{(n_1-1)S^2_1+(N_2-1)S^2_2}{n_1+n_2-2}} = \sqrt{\frac{9*9.2*10^{-4}+9*6.5*10^{-4}}{10+10-2} } = 0.028= 0.03$

$t_{H_0}= \frac{(16.02-16.01)-0}{0.03*\sqrt{\frac{1}{10} +\frac{1}{10} } } = 0.149= 0.15$

The p-value for this test is: 0.882433

The p-value is greater than the significance level, the decision is to not reject the null hypothesis.

Using a significance level of 5%, there is no significant evidence to reject the null hypothesis. You can conclude that the population average of the net volume of the plastic bottles filled by machine one and by machine 2 are equal.

I hope this helps!