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Problem
Problem
The equation
2
sin
x
2
cos
2
x
−
2
sin
x
2
sin
2
x
=
cos
2
x
−
sin
2
x
2\sin\frac{x}{2}\cos^2 x - 2\sin\frac{x}{2}\sin^2 x = \cos^2 x - \sin^2 x
2
sin
2
x
cos
2
x
−
2
sin
2
x
sin
2
x
=
cos
2
x
−
sin
2
x
has a root for which the false statement is a.
sin
2
x
=
1
\sin 2x = 1
sin
2
x
=
1
b.
cos
x
=
1
2
\cos x = \frac{1}{2}
cos
x
=
2
1
c.
cos
2
x
=
−
1
2
\cos 2x = -\frac{1}{2}
cos
2
x
=
−
2
1
d.
cos
x
=
1
\cos x = 1
cos
x
=
1
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