Question

f(x-x分之1)=x平方+x平方分之一,求函数表达式

Answer 1

设x-x分之1=a

f(a)=f(x-1/x)=x^2+1/x^2=(x^2+1/x^2-2)+2=(x-1/x)^2+2=a^2+2

f(a)=a^2+2

f(x)=x^2+2