Target Mathematics

1.17: Cotangent equation and secant identity

0606/12/O/N/17 — Question 11 · 14 marks

(a)
Solve 2cot(ϕ+35)=52\cot(\phi + 35^{\circ}) = 5 for 0ϕ3600^{\circ} \le \phi \le 360^{\circ}.
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(b)(i)
Show that secθcotθ+tanθ=sinθ\tfrac{\sec \theta}{\cot \theta + \tan \theta} = \sin \theta.
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(b)(ii)
Hence solve sec3θcot3θ+tan3θ=32\tfrac{\sec 3\theta}{\cot 3\theta + \tan 3\theta} = -\tfrac{\sqrt{3}}{2} for π2θπ2-\tfrac{\pi}{2} \le \theta \le \tfrac{\pi}{2}, giving your answers in terms of π\pi.
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