Question

Evaluate indefinite integral sec(3x)tan(3x) dx

Answer 1

\[\frac{d}{dx}\sec(3x)=\sec(3x)\tan(3x)3\]

Answer 2

let u=3x, du = 3dx -> du/3 = dx

\[\large \frac{1}{3}\int\limits \sec(u)\tan(u)du =?\]

Answer 3

thanx!!