作业帮两条直线交点坐标怎么算?
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两条直线交点坐标怎么算?
两条直线交点坐标怎么算?
两条直线交点坐标怎么算?
联立两直线方程,
联立方程组求解
line1 (x11,y11)(x12,y12)
line2 (x21,y21)(x22,y22)
(x-x11)/(x12-x11)=(y-y11)/(y12-y11)
=>(x-x11)(y12-y11)=(y-y11)((x12-x11)
=>
(y12-y11)x-(x12-x11)y=x11(y12-y11)-y11(x12-x11)
sa...
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line1 (x11,y11)(x12,y12)
line2 (x21,y21)(x22,y22)
(x-x11)/(x12-x11)=(y-y11)/(y12-y11)
=>(x-x11)(y12-y11)=(y-y11)((x12-x11)
=>
(y12-y11)x-(x12-x11)y=x11(y12-y11)-y11(x12-x11)
same as
(y22-y21)x-(x22-x21)y=x21(y22-y21)-y21(x22-x21)
行列式求
|(y12-y11) -(x12-x11)|
z=| | (z!=0)
|(y22-y21) -(x22-x21) |
|x11(y12-y11)-y11(x12-x11) -(x12-x11)|
x=| | / z
|x21(y22-y21)-y21(x22-x21) -(x22-x21) |
|(y12-y11) x11(y12-y11)-y11(x12-x11)|
y=| | / z
|(y22-y21) x21(y22-y21)-y21(x22-x21)|
收起
联立两直线方程,求解