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September 20, 2014

September 20, 2014

Posted by **Help** on Sunday, April 1, 2012 at 1:09am.

cos(pi/16)

- Trig -
**drwls**, Sunday, April 1, 2012 at 1:57amcos (x/2) = sqrt[(1/2)(1 + cosx)]

cos(pi/16) = sqrt[(1/2)(1 + cos(pi/8)]

cos(pi/8) = sqrt[(1/2)(1 + cos(pi/4)]

= sqrt[(1/2)(1 + sqrt2/2] = 0.92388..

cos(pi/16) = sqrt[(1/2)*1.92388]

= 0.980785..

Writing it in exact form would be a bit messy, but I hope you see how it can be done

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