A micro-electromechanical sensor records a signal SSS as a function of its angular displacement ϕ\phiϕ (measured in radians). The response function is given by
S(ϕ)=4cos3ϕ−5sin2ϕ+3tan4ϕ S(\phi) = 4 \cos 3\phi - 5 \sin 2\phi + 3 \tan 4\phi S(ϕ)=4cos3ϕ−5sin2ϕ+3tan4ϕShow that, for small values of ϕ\phiϕ,
S(ϕ)≈A+Bϕ+Cϕ2 S(\phi) \approx A + B\phi + C\phi^2 S(ϕ)≈A+Bϕ+Cϕ2where A,BA, BA,B and CCC are constants to be found.
Use your answer to part (a) to determine an approximation for
4cos0.21−5sin0.14+3tan0.28 4 \cos 0.21 - 5 \sin 0.14 + 3 \tan 0.28 4cos0.21−5sin0.14+3tan0.28Give your answer to three decimal places.
Practise AQA A Level Maths 1.8 E: Trigonometry with exam-style questions for A Level Maths. 239 questions 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, matched to the AQA A Level Maths (7357) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.