Ok, I've got this equation here,

y=ln((e^x+1)/(e^x-1)

and from this equation I need to find the arc length where p< x < q, p > 0.

I know the formula for the length is the integral from p to q of [1+(dy/dx)^2]^2dx, and I've tried u substitution eventually winding up with the integral from e^p to e^q [(u^2-1)/(u^2+1)*du/u, but here I'm stuck. Does anybody know where to go from here, or if I've just messed it up entirely?

Thanks