Pre-Calculus - Using the sum formula for cosine to evaluate an angle cos(75)

The video tutorial explores the evaluation of the cosine of 75 degrees, emphasizing the importance of finding exact values rather than approximations. It discusses the challenges of evaluating angles not directly on the unit circle and introduces the sum and difference formulas as a solution. The tutorial guides students through applying these formulas to find exact trigonometric values, using the unit circle as a reference.

Explain the formula for the cosine of the sum of two angles.

What are the exact values of cosine for 30 degrees and 45 degrees?

How do you combine the results of cosine and sine to find the cosine of 75 degrees?