设f(x+1/x)=x^2/x^4+1,则f(x)=

Question

设f(x+1/x)=x^2/x^4+1,则f(x)=

Answer 1

设f(x+1/x)
=x^2/x^4+1,
=1/(x²+1/x²)
=1/[(x+1/x)²-2]
则f(x)=1/(x²-2);