1.7 Trigonometry
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Question 81
Figure 1 below shows the right-angled triangle ABCABCABC, in which the angle at C C\,C is a right angle and AB=5AB = 5AB=5 cm.
The angle BAC BAC\,BAC is θ\thetaθ, where θ \theta\,θ is measured in radians.
a.[2]
Given that θ \theta\,θ is small, show that AC≈5−5θ22\displaystyle AC \approx 5 - \frac{5\theta^2}{2}AC≈5−25θ2.
b.[2]
Hence find the length of AC AC\,AC when θ=0.1\theta = 0.1θ=0.1, giving your answer to four decimal places.
1.7 Trigonometry Questions
317 exam-style questions on OCR (MEI) A Level Maths 1.7 Trigonometry, covering 1.7.1 Solve right-angled triangles, 1.7.2 Definitions of sin, cos and tan for any angle, 1.7.3 Graphs of sin, cos and tan, 1.7.4 Exact values of trig functions (degrees), 1.7.5 Area of a triangle, 1.7.6 Sine and cosine rules, 1.7.7 Identity tan = sin/cos, 1.7.8 Identity sin^2 + cos^2 = 1, 1.7.9 Solve simple trigonometric equations, 1.7.10 Exact values of trig functions (radians) (A-level only), 1.7.11 Inverse trigonometric functions (A-level only), 1.7.12 Radians and degree conversion (A-level only), 1.7.13 Arc length and area of a sector (A-level only), 1.7.14 Small angle approximations (A-level only), 1.7.15 Sec, cosec and cot functions (A-level only), 1.7.16 Graphs of reciprocal trig functions (A-level only), 1.7.17 Pythagorean identities for sec and cosec (A-level only), 1.7.18 Compound angle formulae (A-level only), 1.7.19 Double angle identities (A-level only), 1.7.20 Expressions for a cos θ ± b sin θ (A-level only), 1.7.21 Use identities to solve equations (A-level only), 1.7.22 Proofs involving trigonometric functions (A-level only), 1.7.23 Trig to solve problems in context (A-level only), and 1.7 Trigonometry. Each one has a worked solution and a mark scheme showing where the marks go.