Given f(x) = (3x+1)/(x-3),find and write in simplest form:
问题描述：
Given f(x) = (3x+1)/(x-3),find and write in simplest form:
(a) f(f(b))
(b) [f(x)-f(a)]/(x-a)
答
(a) f(f(b))f(b)=(3b+1)/(b-3)f(f(b))=f[(3b+1)/(b-3)]=[3(3b+1)/(b-3)+1]/[(3b+1)/(b-3)-3]=[(9b+3+b-3)/(b-3)]/[(3b+1-3b+9)/(b-3)]=[10b/(b-3)]/[10/(b-3)]=b(b) [f(x)-f(a)]/(x-a)=[(3x+1)/(x-3)-(3a+1)/(a-3)]/...