Evaluate the identity using sum and difference formula

The video tutorial guides viewers through solving a trigonometric problem by working with sine and cosine functions. It begins with setting up the problem, identifying variables, and verifying the formula. The instructor uses a unit circle to aid in calculations, ultimately arriving at the solution. The process is explained step-by-step, ensuring clarity and understanding.

What is the result of cosine of π half as mentioned in the text?

What conclusion is drawn about cosine of X at the end of the discussion?