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May 1, 2016
Posted by **George** on Tuesday, November 13, 2012 at 9:43am.

cos(-x) - sin(-x) = cos(x) + sin(x)

- Precalc -
**Reiny**, Tuesday, November 13, 2012 at 10:18amLS = cos(-x) - sin(-x)

= cosx + sinx

= RS

These are based on standard trig relationships that you should know and recognize