SOLUTION: Express the given trigonometric function in terms of the same function of a positive angle. cos190*, tan 290*

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Question 1052983: Express the given trigonometric function in terms of the same function of a positive angle.
cos190*, tan 290*
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
This problem requires:
1. Knowing how to find the reference angle of any angle.
2. Knowing what the signs of the trig ratios are in
the various quadrants.

190° is in QIII, its reference angle is 190°-180° = 10°
The cosine is negative in QIII, the cosine of 10° in positive.
So cos(190°) = -cos(10°)

290° is in QIV, its reference angle is 360°-290° = 70°
The cosine is positive in QIV, the cosine of 70° in positive.
So cos(290°) = cos(70°)

Edwin