Question 4 - A-Level Maths

Exam Board	CAIE
Module	P3 (Pure Mathematics 3)
Year	2017
Session	November
Topic	Addition & Double Angle Formulae

Prove the identity \(\tan \left( 45 ^ { \circ } + x \right) + \tan \left( 45 ^ { \circ } - x \right) \equiv 2 \sec 2 x\).
Hence sketch the graph of \(y = \tan \left( 45 ^ { \circ } + x \right) + \tan \left( 45 ^ { \circ } - x \right)\) for \(0 ^ { \circ } \leqslant x \leqslant 90 ^ { \circ }\).