Educator

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Example 1:

Derive the formula for cos(A− B) without using the other addition and subtraction formulas.

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Example 2:

Use the addition and subtraction formulas to find the cosines and sines of (π/12)^R and 105^° .

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Example 3:

Use the addition and subtraction formulas to prove the following identity:

sin5x + sinx cos5x + cosx = tan3x

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Example 4:

Use the formula for cos(A− B) and the cofunction identities to derive the other three addition and subtraction formulas.

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Example 5:

Convert 75^°  and -15^° to radians and use the addition and subtraction formulas to find their cosines and sines.

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