(x,y)=(-λ,λ)?你怎麼算的?AP→=λAB→=(-λ,λ)而AP→=(x-1,y)所以有x-1=-λ,y=λx=1-λ,y=λ代入x²+y²-2y≤0得λ²-2λ+1+λ²-2λ≤02λ²-4λ+1≤01-√2/2≤λ≤1
学霸啊，写这么满
