Solve, for 0≤x<360∘0 \leq x < 360^\circ0≤x<360∘,
sin(x−20∘)=12\displaystyle \sin(x - 20^\circ) = \frac{1}{\sqrt{2}}sin(x−20∘)=21
cos3x=−12\displaystyle \cos 3x = -\frac{1}{2}cos3x=−21
10 exam-style questions on Edexcel A Level Old Maths Trigonometry. Each one has a worked solution and a mark scheme showing where the marks go.