Question

函数f(x)=cx/2x+3 ,(x≠-3/2 )满足f[f(x)]=x,则常数c等于-----求帮助,有奖励哦

Answer 1

f[f(x)]=cf(x)/(2f(x)+3)=c*cx/[(2c+6)x+9)=x;

=>c*c=(2c+6)x+9

=>c*c=9;2c+6=0;

=>c=-3