Question

两个复合函数的问题设f（e^x+1）=e^2x+e^x+1,求f(x)设f(x+1/x)=x^2+1/x^2,求f(1/

Answer 1

1、f（e^x+1）=e^2x+e^x+1=[e^x+1)]平方-（e^x+1）+1------令t=e^x+1-------f(t)=t平方-t+1--------f(x)=x平方-x+1

2、f(x+1/x)=x^2+1/x^2=（x+1/x）平方-2---------t=x+1/x-------f(t)=t平方-2---------f(1/x)=(1/x)平方-2