Question

请问下面这道题用直线方程的方法怎么做?

Answer 1

设P(t, 2t+1),

f(t)=PA^2+PB^2=(t-2)^2+(2t+2)^2+t^2+(2t-1)^2=10t^2+9

当t=0时,f(t)最小为9

此时P为(0.1)