Answer:
21
Step-by-step explanation:
Answer:
x=bc-35 over 90
Step-by-step explanation:
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Answer:
a=-8/5
Step-by-step explanation:
(-1/2a-5)=3a+1
To find the opposite of 1/2 a−5, find the opposite of each term.
-1/2a-(-5)= -3a+1
The opposite of −5 is 5.
-1/2a+5=-3a+1
add 3a to both sides
-1/2a+5+3a=1
Combine-1/2and 3a to get 5/2a
5/2a+5=1
Subtract 5 from both side
5/2a=1-5
Subtract 5 from 1 to get −4.
5/2a=-4
Multiply both sides by 2/5 =0.4, the reciprocal of 5/2=2.5.
a=-4x(2/5)
express -4x(2/5)=1.6 as single fraction.
a= -4x2/5
Multiply −4 and 2 to get −8.
a=-8/5
Fraction −8/5 ≈−1.6 can be rewritten as −8/5 =−1.6 by extracting the negative sign.
a=-8/5
First, we have to convert our function (of x) into a function of y (we revolve the curve around the y-axis). So:

And the derivative of x:

Now, we can calculate the area of the surface:

We could calculate this integral (not very hard, but long), or use
(1),
(2) and
(3) to get:



Calculate indefinite integral:

And the area:
![A=2\pi\int\limits_0^{10}x\sqrt{4x^2+1}\,dx=2\pi\cdot\dfrac{1}{12}\bigg[\left(4x^2+1\right)^\frac{3}{2}\bigg]_0^{10}=\\\\\\= \dfrac{\pi}{6}\left[\big(4\cdot10^2+1\big)^\frac{3}{2}-\big(4\cdot0^2+1\big)^\frac{3}{2}\right]=\dfrac{\pi}{6}\Big(\big401^\frac{3}{2}-1^\frac{3}{2}\Big)=\boxed{\dfrac{401^\frac{3}{2}-1}{6}\pi}](https://tex.z-dn.net/?f=A%3D2%5Cpi%5Cint%5Climits_0%5E%7B10%7Dx%5Csqrt%7B4x%5E2%2B1%7D%5C%2Cdx%3D2%5Cpi%5Ccdot%5Cdfrac%7B1%7D%7B12%7D%5Cbigg%5B%5Cleft%284x%5E2%2B1%5Cright%29%5E%5Cfrac%7B3%7D%7B2%7D%5Cbigg%5D_0%5E%7B10%7D%3D%5C%5C%5C%5C%5C%5C%3D%20%5Cdfrac%7B%5Cpi%7D%7B6%7D%5Cleft%5B%5Cbig%284%5Ccdot10%5E2%2B1%5Cbig%29%5E%5Cfrac%7B3%7D%7B2%7D-%5Cbig%284%5Ccdot0%5E2%2B1%5Cbig%29%5E%5Cfrac%7B3%7D%7B2%7D%5Cright%5D%3D%5Cdfrac%7B%5Cpi%7D%7B6%7D%5CBig%28%5Cbig401%5E%5Cfrac%7B3%7D%7B2%7D-1%5E%5Cfrac%7B3%7D%7B2%7D%5CBig%29%3D%5Cboxed%7B%5Cdfrac%7B401%5E%5Cfrac%7B3%7D%7B2%7D-1%7D%7B6%7D%5Cpi%7D)
Answer D.