The expression is equivalent to 1
Trigonometry is a branch of mathematics that studies relationships between side lengths and angles of triangles.
Given:
2cos²(x/2) - cos(x)
We know
cos x= 2cos²(x/2) + 1
2cos²(x/2) = cos x +1
Then,
2cos²(x/2) - cos(x)
= cos x +1 - cos x
=1
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