Edexcel C34 2018 January — Question 9

Exam BoardEdexcel
ModuleC34 (Core Mathematics 3 & 4)
Year2018
SessionJanuary
TopicReciprocal Trig & Identities

  1. (a) Show that
$$\frac { \cot ^ { 2 } x } { 1 + \cot ^ { 2 } x } \equiv \cos ^ { 2 } x$$ (b) Hence solve, for \(0 \leqslant x < 360 ^ { \circ }\), $$\frac { \cot ^ { 2 } x } { 1 + \cot ^ { 2 } x } = 8 \cos 2 x + 2 \cos x$$ Give each solution in degrees to one decimal place.
(Solutions based entirely on graphical or numerical methods are not acceptable.)