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1.8 E: Trigonometry

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Question 136
a.

Given that sin⁡θ≠±1\sin \theta \neq \pm 1sinθ=±1, prove the identity

11−sin⁡θ+11+sin⁡θ≡2sec⁡2θ \frac{1}{1 - \sin \theta} + \frac{1}{1 + \sin \theta} \equiv 2 \sec^2 \theta 1−sinθ1​+1+sinθ1​≡2sec2θ
[3]
b.

Hence, find the set of values of kkk for which the equation

11−sin⁡θ+11+sin⁡θ=k \frac{1}{1 - \sin \theta} + \frac{1}{1 + \sin \theta} = k 1−sinθ1​+1+sinθ1​=k

has real solutions. Fully justify your answer.

[3]
c.

Given that θ\thetaθ is in the second quadrant (angle between 90∘90^\circ90∘ and 180∘180^\circ180∘) and

11−sin⁡θ+11+sin⁡θ=10\frac{1}{1 - \sin \theta} + \frac{1}{1 + \sin \theta} = 101−sinθ1​+1+sinθ1​=10

find the exact value of tan⁡θ\tan \thetatanθ.

[3]
Markscheme

1.8 E: Trigonometry Questions

  1. A Level
  2. /Maths
  3. /1.8 E: Trigonometry

317 exam-style questions on AQA A Level Maths 1.8 E: Trigonometry, covering 1.8.1 Trigonometric definitions, rules and radians, 1.8.2 Small angle approximations (A-level only), 1.8.3 Trigonometric functions and exact values, 1.8.4 Reciprocal and inverse trigonometric functions (A-level only), 1.8.5 Trigonometric identities, 1.8.6 Compound and double angle formulae (A-level only), 1.8.7 Solving trigonometric equations, 1.8.8 Proofs with trigonometric identities, and 1.8.9 Trigonometry in context. Each one has a worked solution and a mark scheme showing where the marks go.

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