Question

高一函数定义域若g(x)=1-2x ,f[g(x)]=(1-x^2)/x^2 ,则f(1/2)=

Answer 1

f[g(x)]=(1-x^2)/x^2(x≠o) g(x)=1-2x 要求的是f(1/2) 可以直接令g(x)=1-2x=1/2,解出x=1/4 将x=1/4代入f[g(x)]=(1-x^2)/x^2 即得f(1/2)=15