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September 30, 2014

September 30, 2014

Posted by **Joe** on Tuesday, February 12, 2013 at 10:22pm.

- Trig/precalc -
**Steve**, Tuesday, February 12, 2013 at 11:03pmcos(x) cos(7pi/4) - sin(x) sin(7pi/4) + cos(x) cos(7pi/4) + sin(x) sin(7pi/4) = 1

2cos(x) cos(7pi/4) = 1

2cos(x) * 1/√2 = 1

cos(x) = 1/√2

x = pi/4 or 7pi/4

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