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February 28, 2015

February 28, 2015

Posted by **BreAnne** on Friday, January 27, 2012 at 6:39pm.

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

- trig -
**Damon**, Friday, January 27, 2012 at 7:03pm3 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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