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2 marksDouble-Angle Formulae

CSEC Additional Mathematics · 2019 · Paper 2 · Question 4(b)(ii)

A right-angled triangle XYZ has an angle, θ, where sin θ = √5 / 5. Without evaluating θ, calculate the exact value (in surd form if applicable) of cos θ.

Calculate the exact value (in surd form if applicable) of sin 2θ.

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Other parts of this question

  1. 4(a)(i)Determine the angle of the sector in radians.[3 marks]
  2. 4(a)(ii)Calculate the perimeter of the sector.[2 marks]
  3. 4(b)(i)Calculate the exact value (in surd form if applicable) of cos θ.[2 marks]
  4. 4(c)Show that tan² θ + 1 = 1/cos² θ.[3 marks]

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