Sketch the graph of
y=4cos2x y = 4 \cos 2x y=4cos2xfor 0≤x≤3π20 \le x \le \frac{3\pi}{2}0≤x≤23π.
The equation
4cos2x=k 4 \cos 2x = k 4cos2x=khas exactly two solutions for the interval 0≤x≤3π20 \le x \le \frac{3\pi}{2}0≤x≤23π. State the possible values of kkk.
Practise AQA A Level Maths 1.8 E: Trigonometry with exam-style questions for A Level Maths. 239 questions covering 1.8.1 Trigonometric definitions, rules and radians, 1.8.2 Small angle approximations (A-level only), 1.8.3 Trigonometric functions and exact values, 1.8.4 Reciprocal and inverse trigonometric functions (A-level only), 1.8.5 Trigonometric identities, 1.8.6 Compound and double angle formulae (A-level only), 1.8.7 Solving trigonometric equations, 1.8.8 Proofs with trigonometric identities, and 1.8.9 Trigonometry in context, matched to the AQA A Level Maths (7357) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.