In this lesson, Julie Harland explains how to derive the formulas for the cosine of the difference of two angles, the sine of the sum of two angles, and the sine of the difference of two angles. She uses the formula for the cosine of the sum of two angles and a few other identities to derive these formulas. The lesson includes examples using the formulas derived.
Uses the formula for the cosine of the sum of two angles to derive the formulas for the cosine of the difference of two angles, the sine of the sum of two angles, and the sine of the difference of two angles. Examples using the formula are provided.
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