How to evaluate for the cosine of an angle using the sum formula

The video tutorial explains how to determine the cosine of 7π/12 using trigonometric identities. It begins by introducing the problem and the lack of a direct point on the unit circle for this angle. The instructor then explains how to use the sum and difference formulas to break down the angle into two known angles, π/4 and π/3. The video emphasizes the importance of understanding the unit circle for efficient evaluation. The instructor demonstrates the step-by-step calculation and simplification process, concluding with a reminder of the method's utility and addressing potential questions.

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