# Trigonometry Examples

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Use the definition of sine to find the known sides of the unit circle right triangle. The quadrant determines the sign on each of the values.

Find the adjacent side of the unit circle triangle. Since the hypotenuse and opposite sides are known, use the Pythagorean theorem to find the remaining side.

Replace the known values in the equation.

Remove parentheses around .

Adjacent

Raise to the power of to get .

Adjacent

Remove parentheses around .

Adjacent

One to any power is one.

Adjacent

Multiply by to get .

Adjacent

Subtract from to get .

Adjacent

Adjacent

Use the definition of cosine to find the value of .

Substitute in the known values.