A student solves cos(2x+15°)=0.3\cos(2x+15°)=0.3cos(2x+15°)=0.3 for 0°⩽x<180° 0°\leqslant x<180°\,0°⩽x<180° and gives only x=28.8°x=28.8°x=28.8°.
Explain why the answer is incomplete and find the complete solution set, giving values to 1 decimal place.
37 exam-style questions on OCR (MEI) A Level Maths 1.7.21 Use identities to solve equations (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.