# Math Help - Integral problem?

1. ## Integral problem?

I dont know why, the solution of this integral is diffrent from my book.
Can u tell me why it is incorrect.

2. ## Re: Integral problem?

This is very difficult to read, is your integral $\displaystyle \int tgh^2x~dx$ ?

3. ## Re: Integral problem?

If thats meant to be tanh x rewrite like this:
$int (tanh^2 x) dx = int (1-sech^2 x) dx$
as $cosh^2 x - sinh^2 x = 1$ divide through by $cosh^2 x$
so you then have:
$x - tanhx + c$
Is that what the answer is meant to be?

4. ## Re: Integral problem?

OH...never mind i considered senh^2x-cosh^2x=1 instead of cosh^2x-senh^2x = 1

thanks for the help.