Use the substitution u=1+2cosxu = 1 + 2\cos xu=1+2cosx to find ∫0π2sinx1+2cosxdx\displaystyle \int_0^{\frac{\pi}{2}} \frac{\sin x}{1 + 2\cos x} dx∫02π1+2cosxsinxdx
59 exam-style questions on Edexcel A Level Maths 11.5 Integration by Substitution. Each one has a worked solution and a mark scheme showing where the marks go.