f(x-1/x)=x2+1/x2则fx=

问题描述:

f(x-1/x)=x2+1/x2则fx=

f(x-1/x)=x2+1/x2=(x-1/x)^2+2
令x-1/x=t,则上式化为:
f(t)=t^2+2;再令t=x
则f(x)=x^2+2