A mechanical linkage is set at an obtuse angle ϕ\phiϕ. The equilibrium position of the linkage is determined by the equation
(4sinϕ+cosϕ)2+(2sinϕ−2cosϕ)2=10.4(4 \sin \phi + \cos \phi)^2 + (2 \sin \phi - 2 \cos \phi)^2 = 10.4(4sinϕ+cosϕ)2+(2sinϕ−2cosϕ)2=10.4
Find the exact value of sinϕ\sin \phisinϕ. Fully justify your answer.
Practise Edexcel A Level Maths 7.5 Proving Trigonometric Identities with exam-style questions for A Level Maths. 27 questions, matched to the Edexcel A Level Maths (9MA0) 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.