I really just cannot win with this stupid stuff.... what the heck am i doing wrong????

Find the volume of the solid obtained by rotating the region bounded by the given curves about the specified axis.
y=1/x^2, y=0, x=1, x=7;
about y=−5

got pi times the integral of ((-5-1/(x^2))^2)+5 from 1 to 7.

which integrates to pi times 30x−10/x−1/3x^3

plug in 7-1 and get 64794pi/343....wrong answer...why can I not do this!! it is taking me 6 hours just to struggle through 5 problems!!! i hate this!

Question

I really just cannot win with this stupid stuff....  what the heck am i doing wrong???? 

Find the volume of the solid obtained by rotating the region bounded by the given curves about the specified axis. 
y=1/x^2, y=0, x=1, x=7; 
about y=−5 

got pi times the integral of ((-5-1/(x^2))^2)+5 from 1 to 7.  

which integrates to pi times 30x−10/x−1/3x^3

plug in 7-1 and get 64794pi/343....wrong answer...why can I not do this!!  it is taking me 6 hours just to struggle through 5 problems!!!  i hate this!

anonymous · Answer

i even tried with the radius being +5 instead of -5 minus the function and still got the wrong answer

and yes, i have a graph already.

terenzreignz · Answer

I admire your passion... :)
You might already have a graph, but I don't... let me try to make a crude representation ^_^

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terenzreignz · Answer

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