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Mathematics
Mathematics
Problem
In Exercises 11-51, prove the identity. 43.
cos
5
x
=
(
1
−
2
sin
2
x
+
sin
4
x
)
(
cos
x
)
\cos ^{5} x=\left(1-2 \sin ^{2} x+\sin ^{4} x\right)(\cos x)
cos
5
x
=
(
1
−
2
sin
2
x
+
sin
4
x
)
(
cos
x
)
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