Figure 1 below shows the graph of y=cosxy = \cos xy=cosx, where x x\,x is measured in radians.
Explain why the equation cosx−3x−0.5=0\cos x - 3x - 0.5 = 0cosx−3x−0.5=0 has only one real root.
Given that the root of the equation is α\alphaα, and that α \alpha\,α is small, use small angle approximations to find the value of α \alpha\,α to three decimal places.
225 exam-style questions on WJEC A Level Maths 3.5 Trigonometry (A-level only), covering 3.5.1 Trigonometry (A-level only), 3.5.2 Trigonometry (A-level only), 3.5.3 Trigonometry (A-level only), 3.5.4 Trigonometry (A-level only), 3.5.5 Trigonometry (A-level only), 3.5.6 Trigonometry (A-level only), 3.5.7 Trigonometry (A-level only), and 3.5.8 Trigonometry (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.