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3 years ago

Please help, trigonometry is hard for me

Mathematics

1 answer:

Vsevolod [243]3 years ago

6 0

Because the cos theta < 0 then theta must be an obtuse angle

so a^2 + b^2 < a^2

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What expression is equivalent to (10x)^-3

irakobra [83]

Answer:

1/ (1000x^3)

Step-by-step explanation:

yes

6 0

3 years ago

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Unoccupied seats on flights cause airlines to lose revenue. Suppose a large airline wants to estimate its average number of unoc

Bingel [31]

Answer:

We need a sample size of at least 719

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.95}{2} = 0.025$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.025 = 0.975$ , so $z = 1.96$

Now, find the margin of error M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

How large a sample size is required to vary population mean within 0.30 seat of the sample mean with 95% confidence interval?

This is at least n, in which n is found when $M = 0.3, \sigma = 4.103$ . So

$M = z*\frac{\sigma}{\sqrt{n}}$

$0.3 = 1.96*\frac{4.103}{\sqrt{n}}$

$0.3\sqrt{n} = 1.96*4.103$

$\sqrt{n} = \frac{1.96*4.103}{0.3}$

$(\sqrt{n})^{2} = (\frac{1.96*4.103}{0.3})^{2}$

$n = 718.57$

Rouding up

We need a sample size of at least 719

6 0

3 years ago

Question 1

gulaghasi [49]

Answer:

217

Step-by-step explanation:

124/4 = 31

31*7 = 217

3 0

3 years ago

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Here are two rectangles.

Sophie [7]

Answer:

$AB=9.5\ cm$

Step-by-step explanation:

step 1

Find the length side PQ

we know that

The area of rectangle PQRS is given by

$A=(PQ)(QR)$

$A=66\ cm^2$

$66=(PQ)(QR)$

substitute the value of QR

$66=(PQ)(12)$

solve for PQ

$PQ=66/12\\PQ=5.5\ cm$

step 2

Find the length side AB

we know that

The perimeter of rectangle ABCD is given by

$P=2(AB+BC)$

we have

$P=30\ cm\\BC=PQ=5.5\ cm$

substitute

$30=2(AB+5.5)$

solve for AB

$15=AB+5.5\\AB=15-5.5\\AB=9.5\ cm$

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3 years ago

On a biology test, Travis got 29 questions correct but did not pass. On a second attempt, he got 38 questions correct. What was

maxonik [38]

Answer:
We know that his first attempt he got 29 questions correct, yet he didn’t pass & the second attempt he got 38 questions correct.
So, If i’m not wrong the percentage increase is 10% [Rounded].

Explanation:
38 - 29 = 9
9 rounded to the nearest tenth is 10%.
Forgive me if I’m wrong, good luck! ^^

3 0

3 years ago

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