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December 19, 2014

December 19, 2014

Posted by **denise** on Sunday, July 24, 2011 at 9:01pm.

- precal 2 -
**Reiny**, Sunday, July 24, 2011 at 10:02pmcos^2x = 1/4

cosx = ± 1/2

do you know an angle x , so that cosx = 1/2 ???

and by the CAST rule, isn't that angle in any of the 4 quadrants?

hint: cos60° = 1/2

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