Answer:
an = 12 -7(n-1)
an = 19-7n
Step-by-step explanation:
The explicit formula for an arithmetic sequence is
an = a1 +d(n-1) where a1 is the first term and d is the common difference
a1 =12
We find d by taking the second term and subtracting the first term
d = 5-12
d = -7
an = 12 -7(n-1)
We can simplify this
an = 12 -7n+7
an = 19-7n
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.
Answer:
Step-by-step explanation:
Given:
27 + 2/3 ÷ 3 + 9/10
In division, compatible numbers are numbers that can be divided mentally.
27 + 2/3 ÷ 3 + 9/10
27 + 0.67 ÷ 3 + 0.9
27.67 ÷ 3.9
= 7.0948717948717
Approximately
= 7
But, alternatively
27.67 ÷ 3.9
27.67 is closer to 28
3.9 is closer to 4
Therefore,
28 ÷ 4
= 7
The quotient of 27 + 2/3 ÷ 3 + 9/10 using compatible numbers is around 7
H+20=35-4H
first, combine your like terms, which are the Hs
add the 4H to both sides, and you will get
5H+20=35
now subtract 20 from both sides, that will cancel out the 20 on the left and leave you with
5H=15
finally, divide both sides by 5 and you will get H=3.
$44.25 .. The perimeter is 19.8, times the cost, which is 44.25