Use the substitution u=1+exu = 1 + e^xu=1+ex to find ∫e3x1+exdx\displaystyle \int \frac{e^{3x}}{1 + e^x} dx∫1+exe3xdx
221 exam-style questions on WJEC A Level Maths 3.7 Integration (A-level only), covering 3.7.1 Integration (A-level only), 3.7.2 Integration (A-level only), 3.7.3 Integration (A-level only), 3.7.4 Integration (A-level only), 3.7.5 Integration (A-level only), and 3.7.6 Integration (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.