Prove that: (cos 3θ + 2cos 5θ + cos 7θ)/(cos θ + 2cos 3θ + cos 5θ) = cos 2θ - sin 2θ tan 3θ.

Question

TextCosine of Sum and Difference of Two AnglesSum to Product Transformation Formulae

Loading...

Prove that cos (π/4 + x) + cos (π/4 – x) = √2 cos x

Prove that (cos 7x + cos 5x) / (sin 7x – sin 5x) = cot x

Prove that (sin 5x – 2sin 3x + sin x) / (cos 5x – cos x) = tan x

TextSum to Product Transformation Formulae

cos (π/4 – x) cos (π/4 – y) – sin (π/4 – x) sin (π/4 – y) = sin (x + y)

cos (π + x) cos (– x) / sin (π – x) cos (π/2 + x) = cot² x

sin (n + 1)x sin (n + 2)x + cos (n + 1)x cos (n + 2)x = cos x