Use the substitution u=1+exu = 1 + e^xu=1+ex to find ∫e4x1+exdx\displaystyle \int \frac{e^{4x}}{1 + e^x} dx∫1+exe4xdx.
119 exam-style questions on CCEA A Level Maths 3.6.4 Integration (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.