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.
5 exam-style questions on OCR (MEI) A Level Maths 1.7.9 Solve simple trigonometric equations. Each one has a worked solution and a mark scheme showing where the marks go.