Question 1076556
The correct right-hand side to make the equation an identity. 

1-cos x
_______ =________
1+ cos x
=================
There's no single "answer."
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It could be
1-cos x
_______ = (1 - cos(x))/(1 + cos(x))
1+ cos x
-----------------
If the problem stated "simplify"
(1 - cos(x))/(1 + cos(x)) = (1 - cos^2(x))/sin^2(x)
But is that simpler?
This problem is a waste of time.