Question

Prove the following

(i) cos(π/2 + x) = - sinx

(ii) sin(π/2 + x) = cosx

(iii) cos(π – x) = – cosx 

(iv) sin(π – x) =sinx 

(v) cos(π + x) = – cosx 

(vi) sin(π + x) = – sinx 

(vii) cos(2π – x) =cosx 

(viii) sin(2π – x) = – sin x.

Answer 1

= 0 - cosx = - cosx