Evaluate Cos pi – x

Answer: Using the trigonometric identity, we can calculate cos(∏-x).

cos (A – B) = cos A + sin A + sin B

Thus,

cos(∏-x)= cos π cos x + sin π sin x

The known values will now be substituted.

We already know that cos π = -1 and sin π = 0.

Hence,

cos(∏-x)= (-1) cos x + sin π sin x

cos(∏-x) = -cosx + 0.

cos(∏-x) = – cos X.