Other than converting degrees to radians and vice versa, section 7-4 was another thing I liked to do. 7-4 has to do with finding refrence angles. All you have to do with this is follow the steps and your good to go. Which is the main reason I like it.
7-4
To find a refrence angle:
1) Find the Quadrant the angle is in.
2) Determine if the trig functions is positive or negative.
3) Subtract 180 from the angle until the absolute value of theta is between 0 and 90.
4) If it is a trig chart angle plug in. If not leave it or plug it into the calculator.
Ex. Find the refrence angle for sin675 degrees
675 degrees is in quadrant 4 where sin is negative.
675-180-180-180=45
sin45 is on the trig chart so your answer is square root of 2/2
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