1.z=ax+by(a,b不同为0)通常转化为y=-(a/b)x+(z/b)在平移后求解.
2.d=x^2+y^2+Dx+Ey+F(E^2+D^2-4F＞0)
即d=(x+D/2)^2+(y+E/2)^2+(4F-D^2-E^2)/4
即点(x,y)到点(-D/2,-E/2)的距离问题
3.k=(y-y0)/(x-x0)(x≠x0)
为点(x,y)到(x0,y0)的斜率.
1.z=ax+by(a,b不同为0)通常转化为y=-(a/b)x+(z/b)在平移后求解.
2.d=x^2+y^2+Dx+Ey+F(E^2+D^2-4F＞0)
即d=(x+D/2)^2+(y+E/2)^2+(4F-D^2-E^2)/4
即点(x,y)到点(-D/2,-E/2)的距离问题
3.k=(y-y0)/(x-x0)(x≠x0)
为点(x,y)到(x0,y0)的斜率.