Edexcel P2 2019 October — Question 9

Exam BoardEdexcel
ModuleP2 (Pure Mathematics 2)
Year2019
SessionOctober
TopicTrig Equations

9. Solutions based entirely on graphical or numerical methods are not acceptable in this question.
  1. Solve, for \(0 \leqslant \theta < 180 ^ { \circ }\), the equation $$3 \sin \left( 2 \theta - 10 ^ { \circ } \right) = 1$$ giving your answers to one decimal place.
  2. The first three terms of an arithmetic sequence are $$\sin \alpha , \frac { 1 } { \tan \alpha } \text { and } 2 \sin \alpha$$ where \(\alpha\) is a constant.
    (a) Show that \(2 \cos \alpha = 3 \sin ^ { 2 } \alpha\) Given that \(\pi < \alpha < 2 \pi\),
    (b) find, showing all working, the value of \(\alpha\) to 3 decimal places.