how can i use the difference identity to find pi/12, because i keep getting 0 when i try it.

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- Mar 25th 2011, 01:26 AMJazKW347pi/12
how can i use the difference identity to find pi/12, because i keep getting 0 when i try it.

- Mar 25th 2011, 01:29 AMProve It
Are you sure you're not trying to find $\displaystyle \displaystyle \sin{\frac{\pi}{12}}$ or $\displaystyle \displaystyle \cos{\frac{\pi}{12}}$?

- Mar 25th 2011, 01:32 AMJazKW347
Ii is Cos(pi/12) i guess i looked at it wrong, i did not see the Cosine

- Mar 25th 2011, 01:44 AMProve It
Either evaluate $\displaystyle \displaystyle \cos{\left(\frac{\pi}{3} - \frac{\pi}{4}\right)}$ using the angle difference identity, or evaluate $\displaystyle \displaystyle \cos{\left(\frac{1}{2}\cdot \frac{\pi}{6}\right)}$ using the half angle identity.