ok, setting u=e^6x du=6e^6x, then dx=du/6u?
then, it would be int(u/u^2+25)du
using the formula int(a^2+u^2) = (1/a)arctan(u/a) + C
i get, (1/5)arctan(e^6x/5)dx or (1/30)arctan(e^6x/5) + C
this is incorrect though because the answer is negative and it should be arctan(5/e^6x) instead of...
Homework Statement
∫(exp(6x))/(exp(12x)+25)dx
Homework Equations
answer: -arctan[5/exp(6*x)]/30
The Attempt at a Solution
honestly, don't know where to start. i was looking at another forum and tried to set u=exp(x) du=exp(x) and dx=du/u. plugging that in i got u^6/(u^12+25)*du/u. not sure...