Pre-Calculus - How to find the exact value by using the sum of two angles formula with cosine

The video tutorial explains how to find the exact value of cosine 75 degrees, which is not directly available on the unit circle. It discusses the limitations of using a calculator for exact values and introduces the angle sum formula to rewrite 75 degrees as a sum of known angles. The tutorial walks through the application of the formula, plugging in values for cosine and sine of 30 and 45 degrees, and demonstrates how to simplify the result. It also highlights the importance of understanding the unit circle and the need for simplification in mathematical expressions.

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

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What is the cosine of 30 degrees and how is it derived from the unit circle?

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How can the expression sqrt(6)/4 - sqrt(2)/4 be simplified further?

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