# Indefinite Integral (Inverse trigonometric functions)

How to evaluate this given expression? $$\int\frac{du}{\sqrt{9e^{-2u}-1}}$$ I got so many tries but I'm not sure of my answer because somebody said that it was wrong, they told me that I used a wrong formula applied! That's why I ask a support here I want correct explanation and answer of this given!

Thanks!

• Write down your answer, let us differentiate it and we shall check who's wrong: you or that somebody. Jan 31 '18 at 9:41