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2 years ago

I need help pls I will give brainliest

Mathematics

2 answers:

Alik [6]2 years ago

5 0

Answer:

Step-by-step explanation:

puteri [66]2 years ago

3 0

B-

You know straight away from the fact 5x-6 is -30 so none of the others work

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A decorative hat is shaped like a cone. The hat has a 7 inch diameter and an 8 inch height.

svetoff [14.1K]

Step-by-step explanation:

the answer to this question is 410.29

sorry if this is wrong

4 0

2 years ago

From a distance of 110 m, the angle of elevation to the top spire of a tower is 31°.

sesenic [268]

Answer:

63.51 m

Step-by-step explanation:

TOA

let o be the height of the building

tan31°=o/110m

0=110m tan31°

o=63.51m

8 0

2 years ago

20% of US High School teens vape. A local High School has implemented campaigns to reduce vaping among students and believes tha

zaharov [31]

Answer:

10.93% probability of observing 51 or fewer vapers in a random sample of 300

Step-by-step explanation:

I am going to use the normal approximation to the binomial to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

Normal probability distribution

Problems of normally distributed samples can be 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.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

In this problem, we have that:

$n = 300, p = 0.2$

$\mu = E(X) = np = 300*0.2 = 60$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{300*0.2*0.8} = 6.9282$

What is the approximate probability of observing 51 or fewer vapers in a random sample of 300?

Using continuity corrections, this is $P(X \leq 51 + 0.5) = P(X \leq 51.5)$ , which is the pvalue of Z when X = 51.5 So

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

$Z = \frac{51.5 - 60}{6.9282}$

$Z = -1.23$

$Z = -1.23$ has a pvalue of 0.1093.

10.93% probability of observing 51 or fewer vapers in a random sample of 300

4 0

3 years ago

According to data from a medical association, the rate of change in the number of hospital outpatient visits, in millions, in

GaryK [48]

Answer:

a) $f(t)=0.001155[\frac{2}{3}t(t-1980)^{3/2}-\frac{4}{15}(t-1980)^{5/2}]+264,034,000$

b) f(t=2015) = 264,034,317.7

Step-by-step explanation:

The rate of change in the number of hospital outpatient visits, in millions, is given by:

$f'(t)=0.001155t(t-1980)^{0.5}$

a) To find the function f(t) you integrate f(t):

$\int \frac{df(t)}{dt}dt=f(t)=\int [0.001155t(t-1980)^{0.5}]dt$

To solve the integral you use:

$\int udv=uv-\int vdu\\\\u=t\\\\du=dt\\\\dv=(t-1980)^{1/2}dt\\\\v=\frac{2}{3}(t-1980)^{3/2}$

Next, you replace in the integral:

$\int t(t-1980)^{1/2}=t(\frac{2}{3}(t-1980)^{3/2})- \frac{2}{3}\int(t-1980)^{3/2}dt\\\\= \frac{2}{3}t(t-1980)^{3/2}-\frac{4}{15}(t-1980)^{5/2}+C$

Then, the function f(t) is:

$f(t)=0.001155[\frac{2}{3}t(t-1980)^{3/2}-\frac{4}{15}(t-1980)^{5/2}]+C'$

The value of C' is deduced by the information of the exercise. For t=0 there were 264,034,000 outpatient visits.

Hence C' = 264,034,000

The function is:

$f(t)=0.001155[\frac{2}{3}t(t-1980)^{3/2}-\frac{4}{15}(t-1980)^{5/2}]+264,034,000$

b) For t = 2015 you have:

$f(t=2015)=0.001155[\frac{2}{3}(2015)(2015-1980)^{1/2}-\frac{4}{15}(2015-1980)^{5/2}]+264,034,000\\\\f(t=2015)=264,034,317.7$

3 0

3 years ago

If sin x = .21, what is cos x

nika2105 [10]

0.999993283193413 is the answer. You may have to round.

6 0

3 years ago