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February 28, 2015

February 28, 2015

Posted by **Kayla** on Thursday, March 18, 2010 at 11:05am.

- trig -
**drwls**, Thursday, March 18, 2010 at 11:13amUse algebra to solve for the variable cos x. The equation we are solving will look simler if give that cos x a new name, y.

2y^2 +y -1 = 0

That equation can be factored as follows:

(2y -1)(y+1) = 0

This means that y = 1/2 or y = -1. Both are solutions. The corresponding angles are:

60 degrees, 300 degrees and 180 degrees.

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