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3 years ago

I need the answer to be proper in simple steps

Mathematics

1 answer:

Stella [2.4K]3 years ago

6 0

Answer:

a) φ = 4/7

b) φ = 4

Step-by-step explanation:

The relationship between radius, angle, and arc length is ...

a = r·φ . . . . . φ in radians

You want to find the angle φ, so you can divide this equation by r:

φ = a/r

a) φ = a/r = (8 cm)/(14 cm) = 8/14

φ = 4/7 radians

b) φ = a/r = (16 cm)/(4 cm) = 16/4

φ = 4 radians

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Brewed decaffeinated coffee contains some caffeine. We want to estimate the amount of caffeine in 8 ounce cups of decaf coffee a

rusak2 [61]

Answer:

We would have to take a sample of 62 to achieve this result.

Step-by-step explanation:

Confidence level of 95%.

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 $1 - \alpha$ .

That 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.

Assume that the standard deviation in the amount of caffeine in 8 ounces of decaf coffee is known to be 2 mg.

This means that $\sigma = 2$

If we wanted to estimate the true mean amount of caffeine in 8 ounce cups of decaf coffee to within /- 0.5 mg, how large a sample would we have to take to achieve this result?

We would need a sample of n.

n is found when $M = 0.5$ . So

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

$0.5 = 1.96\frac{2}{\sqrt{n}}$

$0.5\sqrt{n} = 2*1.96$

Dividing both sides by 0.5

$\sqrt{n} = 4*1.96$

$(\sqrt{n})^2 = (4*1.96)^2$

$n = 61.5$

Rounding up

We would have to take a sample of 62 to achieve this result.

8 0

3 years ago

If , n^-3 = 1/8 then n would be which of the following? -1/2 -2 2 1/2

lions [1.4K]

Answer:

Step-by-step explanation:

${n}^{ - 3} = \frac{1}{8} \\ \\ {n}^{ - 3} = \frac{1}{ {2}^{3} } \\ \\ {n}^{ - 3} = {2}^{ - 3}.. (\because \frac{1}{a^n} = a^{-n}) \\ \\ n = 2 \\(\because exponents \: are \: same\: hence\: \\bases\: will \: also\: be\: equal)$