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3 years ago

Help with calculus please?

1 answer:

3 0

Wait let me know that the .12 means in the first question and i will fix the answer

int (x)(cosx) dx

u=x ----> take derivative du=dx
dv=cosx -----> take integral v=sinx

now use integration by parts

u v - int (v)du
x sinx - int (sinx) (1) dx=

x sinx - (-cos(x)) + c =

answer is = x sinx + cosx + c

You might be interested in

X^2=7^2+8^2-2(7)(8)(cos32)

Natasha_Volkova [10]

Answer:

x ≈4.244833711

Step-by-step explanation:

x^2=7^2+8^2-2(7)(8)(cos32)

Determine the powers

x^2=49+64-2(7)(8)(cos32)

Multiply from left to right

x^2 = 49+64 - 112cos32

x^2 = 49+64 - 94.98138677

Add and subtract

x^2 =113-94.98138677

x^2 = 18.01861323

Take the square root of each side

sqrt(x^2) = sqrt(18.01861323)

x = sqrt(18.01861323)

x ≈4.244833711

x^2 =113

3 0

3 years ago

bella and camila are gathering leaves for their nature collection. bella has 18 leaves. camilla has twice as many leaves as bell

vaieri [72.5K]

Answer:

Step-by-step explanation:

18 + 18 is like 36 divied by 2 is 18 then dvide that by two is 9 so 9

8 0

2 years ago

Of the total population of American households, including older Americans and perhaps some not so old, 17.3% receive retirement

Alex Ar [27]

Answer:

47.54% probability that more than 20 households but fewer than 35 households receive a retirement income

Step-by-step explanation:

We use the binomial aproxiation to the normal 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:

$p = 0.173, n = 120$ . So

$\mu = E(X) = np = 120*0.173 = 20.76$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{120*0.173*0.827} = 4.14$

In a random sample of 120 households, what is the probability that more than 20 households but fewer than 35 households receive a retirement income?

We are working with discrete values, so this is the pvalue of Z when X = 35-1 = 34 subtracted by the pvalue of Z when X = 20 + 1 = 21.

X = 34

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

$Z = \frac{34 - 20.76}{4.14}$