Target Mathematics

1.27: Secant identity and squared sine equation

0606/13/M/J/19 — Question 6 · 10 marks

(a)(i)
Show that secθtanθcscθ=cosθ\sec \theta - \tfrac{\tan \theta}{\csc \theta} = \cos \theta.
[3]
(a)(ii)
Solve sec2θtan2θcsc2θ=32\sec 2\theta - \tfrac{\tan 2\theta}{\csc 2\theta} = \tfrac{\sqrt{3}}{2} for 0θ1800^{\circ} \le \theta \le 180^{\circ}.
[3]
(b)
Solve 2sin2(ϕ+π3)=12\sin^{2}\left(\phi + \tfrac{\pi}{3}\right) = 1 for 0<ϕ<2π0 < \phi < 2\pi radians.
[4]