设P(x,y)是圆x2+y2-8x-6y+16=0上一点,则y/x的最大是什么?

Answer 1

用三角函数的方法解最简单.
x^2+y^2-8x-6y+16=0
x^2-8x+16+y^2-6y+9=9
(x-4)^2+(y-3)^2=9
令x=4+3cosa,y=3+3sina
y/x=(3+3sina)/(4+3cosa)
-1