SOLUTION: Verify The Equation is an Identity cosx*cos(-x)-sinx*sin(-x)=1 how do I do it???

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Question 434491: Verify The Equation is an Identity
cosx*cos(-x)-sinx*sin(-x)=1
how do I do it???
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Verify The Equation is an Identity
cosx*cos(-x)-sinx*sin(-x)=1
..
cos(-x)=cos(x) (cos is an even function)
sin (-x)=-sinx (sin is an odd function)
..
cosx*cos(-x)-sinx*sin(-x)
cosx*cosx-(sinx*(-sinx)=cos^2x+sin^2x=1