1.y=f(x)的反函数：y+3=log2(x)+2,即y=log2(x)-1.
y=f(x):x=log2(y)-1,log2(y)=x+1,y=2^(x+1).
2.（xa-yb）*a=0,(3x-4y,4x-3y)*(3,4)=0,9x-12y+16x-12y=0,25x=24y.
|xa-xb|=1,因为a-b=(-1,1),x^2+x^2=1,x=√2/2,y=25√2/48.
3.设为(x,y).(-x+√3y)/(2*1)=√2/2,又因为x2+y2=1,4x^2+2√2x-1=0,
((-√2+√6)/4,(√2+√6)/4)或((-√2-√6)/4,(√6-√2)/4).
累死了Orz...