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April 25, 2014

April 25, 2014

Posted by **Edan** on Thursday, November 5, 2009 at 6:38pm.

cos 60°=1-2 sin² 30°

- Trigonometry -
**bobpursley**, Thursday, November 5, 2009 at 6:47pmI am not certain what I am seeing.

Is it

cos^2 60=1-2sin^2 30 ?

3/4=?=1-2*1/4

so it doesn't verify...so I must not be seeing the type clearly

- Trigonometry -
**Edan**, Friday, November 6, 2009 at 12:01amThis is exacly how the question goes, This is a test question.

1.Using exact values, verify that

cos 60°=1-2 sin² 30°

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