A mechanical system's variable torque τ\tauτ, in Newton-metres, is modeled as a function of its angular displacement θ\thetaθ (in radians) by the equation τ(θ)=14θsin(12θ)\displaystyle \tau(\theta) = \frac{1}{4}\theta \sin\left(\frac{1}{2}\theta\right)τ(θ)=41θsin(21θ). Prove that the total work done W=∫02πτ(θ) dθW = \int_{0}^{2\pi} \tau(\theta) \, d\thetaW=∫02πτ(θ)dθ is equal to exactly π \pi\,π Joules.
864 exam-style questions on Edexcel A Level Maths Integration, covering 11.1 Integrating Standard Functions, 11.2 Integrating f(ax + b), 11.3 Using Trigonometric Identities, 11.4 Reverse Chain Rule, 11.5 Integration by Substitution, 11.6 Integration by Parts, 11.7 Partial Fractions, 11.8 Finding Areas, 11.9 The Trapezium Rule, 11.10 Solving Differential Equations, and 11.11 Modelling with Differential Equations. Each one has a worked solution and a mark scheme showing where the marks go.