Complete the identity cos x 11 pi6 A Squareroot 32 cos x

Complete the identity. cos (x - 11 pi/6) =? A. Squareroot 3/2 (cos x - sin x) B. 1/2 (Squareroot 3 cos x - sin x) C. -Squareroot 3/2 (cos x - sin x) D. -Squareroot 3/2 (cos x + sin x)

Solution

cos(x-11pi/6)

cos x cos (11pi/6)+ sin x sin(11pi/6)

cos x(sqrt3/2) + sin x(-1/2)

(sqrt 3/2)cos x-(1/2)sin x

(1/2)(sqrt3 cos x -sinx)

Correct option is B