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## Homework Statement

This is actually part of this problem: find the surface area of (1/x) rotated about the x axis from 1 to infinity

## Homework Equations

Surface Area=∫2[itex]\pi[/itex]y[itex]\sqrt{1+(dy/dx)^2}[/itex]

## The Attempt at a Solution

I took the derivative of (1/x)=-1/x^2

so I have ∫2[itex]\pi[/itex](1/x)[itex]\sqrt{1+1/x^4}[/itex]

=∫2[itex]\pi[/itex](1/x)[itex]\sqrt{(x^4+1)/x^4}[/itex]

and got 2[itex]\pi[/itex][itex]\sqrt{(x^4+1)}/x^3[/itex]

Now I'm stuck. I can't do trig sub since they aren't powers of 2, x^4+1 isn't a perfect square, so what should I do now????