Cofunction identities and how to determine cofunctions given a function value.

How to use cofunction identities to solve trigonometric equations?

Example:

Find a possible acute angle solution.

a) cos(2θ + 16°) = sin(θ + 11°)

b) cot(θ) = tan(θ + π/6)

How to use power reducing formulas to simplify trigonometric expressions?

It contains the power reducing trigonometric identities for sine, cosine, and tangent.

Examples:

sin

sin

sin

Find the exact value of the following:

sin (22.5°)

Find the exact value of the following:

tan(105°)

Find the exact value of the following:

sin(a/2) if cos a = 3/5 for 0° ≤ a ≤ 90°

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