How do you prove #cos (-x)+cos (pi-x) = cos (pi+x) + cosx#?
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1 Answer
Mar 25, 2016
Proving equation
Explanation:
Prove the equation by using the trig unit circle.
On the unit circle,
cos (-x) = cos x
The left side of the equation --> cos x - cos x = 0
On the right side,
The right side --> - cos x + cos x = 0
That proves the equation.
