Show that the equation
4sin2x+9cosx−6=0 4 \sin^2 x + 9 \cos x - 6 = 0 4sin2x+9cosx−6=0can be written as
4cos2x−9cosx+2=0. 4 \cos^2 x - 9 \cos x + 2 = 0. 4cos2x−9cosx+2=0.Hence solve, for 0≤x<720∘0 \leq x < 720^\circ0≤x<720∘,
4sin2x+9cosx−6=0, 4 \sin^2 x + 9 \cos x - 6 = 0, 4sin2x+9cosx−6=0,giving your answers to 1 decimal place.
Practise Edexcel A Level Old Maths Trigonometry with exam-style questions for A Level Old Maths. 13 questions, matched to the Edexcel A Level Old Maths (9371) specification and written in Unit exams C1, C2, C3 and C4 plus two applied units (e.g. S1 and M1) 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.