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sin
(
2
x
)
=
2
sin
(
x
)
cos
(
x
)
{\displaystyle \sin(2x)=2\sin(x)\cos(x)}
cos
(
2
x
)
=
cos
2
(
x
)
−
sin
2
(
x
)
{\displaystyle \cos(2x)=\cos ^{2}(x)-\sin ^{2}(x)}
tan
(
2
x
)
=
2
tan
(
x
)
1
−
tan
2
(
x
)
{\displaystyle \tan(2x)={\frac {2\tan(x)}{1-\tan ^{2}(x)}}}
cos
2
(
x
)
=
1
+
cos
(
2
x
)
2
{\displaystyle \cos ^{2}(x)={\frac {1+\cos(2x)}{2}}}
sin
2
(
x
)
=
1
−
cos
(
2
x
)
2
{\displaystyle \sin ^{2}(x)={\frac {1-\cos(2x)}{2}}}
