Finding a negative exact value of a trig function is very similar to solving when an angle is greater than 360 degrees.
We know that the unit circle begins at zero degrees and goes all the way up to 360 degrees. For anything outside of that range, we must use properties of coterminal angles to solve and find the corresponding degrees/coordinates on the unit circle.
Suppose that you were given an angle of -120 degrees. Since that's not on the Unit Circle, we would add 360 and finding its corresponding degrees and coordinates. We could then use those (x, y) coordinates to find the exact values of sine, cosine, tangent, cotangent, secant, and cosecant at that degree.
Review sheets due tomorrow for everyone except 6th period - yours are due Monday.
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