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)=
,求f(x)的解析式. 1 sin2x•cos2x
答
∵f(tanx)=
1 sin2x•cos2x
=
4 (2sinxcosx)2
=
4
sin22x
=(
)22 sin2x
=(
)2,1+tan2x tanx
∴f(x)=(
)21+x2
x
=
+x2+2(x≠0).1 x2