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tangare [24]
3 years ago
7

2/5(r-2)=3/20(r-4) What is r?

Mathematics
2 answers:
Luden [163]3 years ago
5 0
R equals approximately 4/5
Dmitrij [34]3 years ago
3 0
<span> r = 4/5 I do believe.</span>
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First make a substitution and then use integration by parts to evaluate the integral. (Use C for the constant of integration.) x
e-lub [12.9K]

Answer:

(\frac{x^{2}-25}{2})ln(5+x)-\frac{x^{2}}{4}+\frac{5x}{2}+C

Step-by-step explanation:

Ok, so we start by setting the integral up. The integral we need to solve is:

\int x ln(5+x)dx

so according to the instructions of the problem, we need to start by using some substitution. The substitution will be done as follows:

U=5+x

du=dx

x=U-5

so when substituting the integral will look like this:

\int (U-5) ln(U)dU

now we can go ahead and integrate by parts, remember the integration by parts formula looks like this:

\int (pq')=pq-\int qp'

so we must define p, q, p' and q':

p=ln U

p'=\frac{1}{U}dU

q=\frac{U^{2}}{2}-5U

q'=U-5

and now we plug these into the formula:

\int (U-5)lnUdU=(\frac{U^{2}}{2}-5U)lnU-\int \frac{\frac{U^{2}}{2}-5U}{U}dU

Which simplifies to:

\int (U-5)lnUdU=(\frac{U^{2}}{2}-5U)lnU-\int (\frac{U}{2}-5)dU

Which solves to:

\int (U-5)lnUdU=(\frac{U^{2}}{2}-5U)lnU-\frac{U^{2}}{4}+5U+C

so we can substitute U back, so we get:

\int xln(x+5)dU=(\frac{(x+5)^{2}}{2}-5(x+5))ln(x+5)-\frac{(x+5)^{2}}{4}+5(x+5)+C

and now we can simplify:

\int xln(x+5)dU=(\frac{x^{2}}{2}+5x+\frac{25}{2}-25-5x)ln(5+x)-\frac{x^{2}+10x+25}{4}+25+5x+C

\int xln(x+5)dU=(\frac{x^{2}-25}{2})ln(5+x)-\frac{x^{2}}{4}-\frac{5x}{2}-\frac{25}{4}+25+5x+C

\int xln(x+5)dU=(\frac{x^{2}-25}{2})ln(5+x)-\frac{x^{2}}{4}+\frac{5x}{2}+C

notice how all the constants were combined into one big constant C.

7 0
3 years ago
The owner of a fish market has an assistant who has determined that the weights of catfish are normally​ distributed, with mean
LiRa [457]

Answer:

P(X\geq 3.4)=0.0228

Step-by-step explanation:

Given the mean is 3.2, standard deviation is 0.8 and the sample size is 64.

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#First determine the z-value:

z=\frac{\bar X -\mu}{\sigma/\sqrt{n}}\\\\=\frac{3.4-3.2}{0.8/\sqrt{64}}\\\\=2.000

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Z(X\geq 3.4)=1-P(X

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What happens to the Law of Cosines if the known angle is 90 degrees?
poizon [28]

Answer:

See below.

Step-by-step explanation:

It transforms  to the Pythagoras theorem.

c^2  = a^2 + b^2 - 2ab cos C

If C = 90,  cos C = zero so the last term disappears.

c^2  = a^2 + b^2 - 2ab * 0

c^2 = a^2 + b^2.

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3 years ago
Is 4(x+2y) and 8y+4x Equivalent
Illusion [34]
Yes.

When you use distributive property in first expression you’ll get 4x +8y. The second expression just rearranged those two terms.
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2 years ago
Someone help a person in need
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Answer:

B I hope this helps.......

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