A calculus student is verifying the derivative formulas for trigonometric functions of uuu. Using the derivatives ddu(sinu)=cosu\displaystyle \frac{d}{du}(\sin u) = \cos udud(sinu)=cosu and ddu(cosu)=−sinu\displaystyle \frac{d}{du}(\cos u) = -\sin udud(cosu)=−sinu, help them prove that:
333 exam-style questions on WJEC A Level Maths 3.6 Differentiation (A-level only), covering 3.6.1 Differentiation (A-level only), 3.6.2 Differentiation (A-level only), 3.6.3 Differentiation (A-level only), 3.6.4 Differentiation (A-level only), 3.6.5 Differentiation (A-level only), 3.6.6 Differentiation (A-level only), 3.6.7 Differentiation (A-level only), and 3.6 Differentiation (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.