How do you integrate int (e^x+e^-x)/(e^x-e^-x)dx?

1 Answer
Feb 20, 2017

int (e^x + e^-x)/(e^x - e^-x)dx = ln|sinhx| + C = ln|1/2(e^x -e^-x)| + C

Explanation:

We know that

•coshx = (e^x + e^-x)/2
•sinhx = (e^x- e^-x)/2

This integral can be rewritten as

int coshx/sinhx dx, where coshx and sinhx represent the hyperbolic trigonometric functions

Now use a substitution to solve. Let u = sinhx. Just like with regular trigonometric functions, du = coshx dx and dx= (du)/coshx.

int coshx/u * (du)/coshx

int 1/u du

ln|u| + C

ln|sinhx| + C

If you wish, the answer can be written as

ln|1/2(e^x - e^-x)| + C

Hopefully this helps!