已知函数f(x)满足f(tanx)=1/sin2x•cos2x,求f(x)的解析式.

问题描述:

已知函数f(x)满足f(tanx)=

1
sin2x•cos2x
,求f(x)的解析式.

∵f(tanx)=

1
sin2x•cos2x

=
4
(2sinxcosx)2

=
4
sin22x

=(
2
sin2x
)
2

=(
1+tan2x
tanx
)
2

∴f(x)=(
1+x2
x
)
2

=
1
x2
+x2+2(x≠0).