Question

高一数学，不懂的走开，过程很重要！！

Answer 1

let
f(x)=ax+b
f(f(x)) = a(ax+b) +b = 1+2x
=>
a^2=2 (1) and
ab+b=1 (2)

from (1)
a=√2 or -√2

when a=√2
from (2)
√2b +b=1
b = 1/(√2+1)
= √2-1

when a=-√2
from (2)
-√2b +b=1
b = 1/(1-√2)
= -(1+√2)

f(x) = √2x + (√2-1) or -√2x -(1+√2)

Answer 2

设t=x
f(t)=a+bt
f(f(t))=a+b(a+bt)=a+ab+b^2t=1+2t
b=±根号2，a=±（根号2-1）
还原则是f（x）=根号2x+根号2-1，或者 -根号2x-根号2+1

Answer 3

求人帮忙如此态度怎么可以呢？好像别人欠你的？