Question 3 - A-Level Maths

Edexcel C2 — Question 3 8 marks

Exam Board	Edexcel
Module	C2 (Core Mathematics 2)
Marks	8
Paper	Download PDF ↗
Mark scheme	Download PDF ↗
Topic	Quadratic trigonometric equations
Type	Direct solve: sin²/cos² substitution
Difficulty	Moderate -0.3 This is a standard C2 trigonometric equation requiring the identity cos²θ = 1 - sin²θ to convert to a quadratic in sin θ, then solving 3sin²θ - 2sinθ - 1 = 0. The technique is routine for this level, though finding all solutions in the given interval requires care with signs and reference angles.
Spec	1.05j Trigonometric identities: tan=sin/cos and sin^2+cos^2=1 1.05o Trigonometric equations: solve in given intervals

3. Find the values of $\theta$, to 1 decimal place, in the interval $- 180 \leq \theta < 180$ for which $$2 \sin ^ { 2 } \theta ^ { \circ } - 2 \sin \theta ^ { \circ } = \cos ^ { 2 } \theta ^ { \circ }$$ [P1 January 2002 Question 3]

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3. Find the values of $\theta$, to 1 decimal place, in the interval $- 180 \leq \theta < 180$ for which

$$2 \sin ^ { 2 } \theta ^ { \circ } - 2 \sin \theta ^ { \circ } = \cos ^ { 2 } \theta ^ { \circ }$$

[P1 January 2002 Question 3]\\

\hfill \mbox{\textit{Edexcel C2  Q3 [8]}}

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