# trig

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What is cos(11pi/3)? Explain your thinking.

What is sin(13pi/4) ? Explain your thinking.

• trig -

3 2/3 pi
3 pi ends up at 180 degrees (2 pi + pi)
2/3 pi = 120 degrees
180 + 120 = 300 = 360 - 60
so 60 degrees below x axis in quadrant 4
cos -60 = 1/2
so
cos (11 pi/3) = 1/2
Now you do any more like that.

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