Question

rewrite cos(x- 5pi/3) in terms of sin(x) and cos(x)

Answer 1

I will use 300° instead of 5π/3 (I can visualize the unit circle better in degrees, that is just me)

cos(x-300°) = cosxcos300 + sinxsin300
we know cos300° = 1/2, and sin300° = -√3/2
= (1/2)cosx - (√3/2)sinx