Question

How do you evaluate the integral `int 2^x/(2^x+1)`?

Answer 1

`ln(2^x+1)/ln 2+C`

Explanation:

Since `d/dx(2^x+1)=2^x ln 2`, we have

`int 2^x/(2^x+1)dx = 1/ln 2 int {d(2^x+1)}/(2^x+1) = ln(2^x+1)/ln 2+C`