Given that
5cosθ−12sinθ≡Rcos(θ+α) 5 \cos \theta - 12 \sin \theta \equiv R \cos(\theta + \alpha) 5cosθ−12sinθ≡Rcos(θ+α)find the value of RRR, where R>0R > 0R>0.
Circle the correct answer from the options below:
555 \qquad 777 \qquad 131313 \qquad 171717
137 exam-style questions on Edexcel A Level Maths Trigonometry and Modelling, covering 7.1 Addition Formulae, 7.2 Double Angle Formulae, 7.3 Solving Trigonometric Equations, 7.4 Simplifying a cos x +- b sin x, 7.5 Proving Trigonometric Identities, and 7.6 Modelling with Trigonometric Functions. Each one has a worked solution and a mark scheme showing where the marks go.