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July 30, 2015

July 30, 2015

Posted by **Haley** on Wednesday, November 28, 2012 at 9:47pm.

1) cos(345°)

- pre-calc help !!!!!!! -
**Reiny**, Wednesday, November 28, 2012 at 10:22pmdid you notice that 345 = 360-15 ?

cos(345)

= cos15

cos15 = cos(45-30)

= cos45cos30 + sin45sin30

= (√2/2)(√3/2) + (√2/2)(1/2)

= ( √6 + √2)/4

cos 345 = (√6+√2)/4