(i)[4]
Prove that $\tan(45^\circ + x) + \tan(45^\circ - x) = 2\sec 2x$.
(ii)[3]
Hence sketch $y = \tan(45^\circ + x) + \tan(45^\circ - x)$ for $0^\circ \leq x \leq 90^\circ$.
(c(ii))[3]
Hence sketch $y = \tan(45^\circ + x) + \tan(45^\circ - x)$ for $0^\circ \leq x \leq 90^\circ$.