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2 years ago

5

Simplify expression. help me please

1 answer:

tatuchka [14]2 years ago

6 0

Answer:

$\frac{-1}{x+3}$

Step-by-step explanation:

Hope this helps!

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Sin(x+ pi/6)- sin(x-pi/6)= 1/2

agasfer [191]

Answer:

You can download the answer here. Link below!

5 0

2 years ago

A manufacturer knows that their items have a normally distributed lifespan, with a mean of 5.5 years, and standard deviation of

Alina [70]

Answer:

If 24 items are picked at random, 8% of the time their mean life will be less than 5.156 years.

Step-by-step explanation:

To solve this question, we have to understand the normal probability distribution and the central limit theorem.

Normal probability distribution:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central limit theorem:

The Central Limit Theorem estabilishes that, for a random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sample means with size n of at least 30 can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$

In this problem, we have that:

$\mu = 5.5, \sigma = 1.2, n = 24, s = \frac{1.2}{\sqrt{24}} = 0.2449$

If 24 items are picked at random, 8% of the time their mean life will be less than how many years?

This is the value of X when Z has a pvalue of 0.08. So it is X when Z = -1.405.

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$-1.405 = \frac{X - 5.5}{0.2449}$

$X - 5.5 = -1.405*0.2449$

$X = 5.156$

If 24 items are picked at random, 8% of the time their mean life will be less than 5.156 years.

3 0

3 years ago

Find the number that makes the ratio equivalent to 1:8.<br> 7:__

kvasek [131]

Answer:

56

Step-by-step explanation:

1:8= 7:?

1*?=7

/1 /1

1*7=7

8*7=56

1:8 = 7:56

4 0

3 years ago

Read 2 more answers

Liza is driving to her sister's house 360 miles away. After 4 hours, Liza is 2 3 of the way there.

DochEvi [55]

Liza is driving to her sister's house 360 miles away. After 4 hours, Liza is 2/3 of the way there. How many more hours does Liza have to drive?

<em><u>Answer:</u></em>

Liza need to drive 2 more hours to reach her sister house

<em><u>Solution:</u></em>

Given that Liza is driving to her sister's house 360 miles away

So total distance = 360 miles

After 4 hours, Liza is 2/3 of the way there.

$\frac{2}{3} r d \text { of total distance }=\frac{2}{3} \times 360=240$

So Liza has covered 240 miles in 4 hours

Let us find the speed

<em><u>The relation between distance and speed is given as:</u></em>

$speed = \frac{distance}{time}$

$speed = \frac{240}{4} = 60$

Thus speed = 60 miles per hour

Assuming speed is same throughout the journey, let us calculate the time taken to complete remaining distance

Remaining distance = 360 - 240 = 120 miles

Now distance = 120 miles and speed = 60 miles per hour

$time taken = \frac{distance}{speed}\\\\time taken = \frac{120}{60} = 2$

Thus Liza need to drive 2 more hours to reach her sister house

4 0

3 years ago

GIVING OUT BRAINLIEST TO WHOEVER CAN PROVIDE THE CORRECT ANSWER !! Asap

saul85 [17]

Answer:

139.48

Step-by-step explanation:

cos(55)=80/x

80/cos(55)=x

4 0

3 years ago