点到任意直线的距离

point (x,y)到line a*x &＃43; b*y &＃43; c &＃61; 0 的距离计算.
代码很简单,只是为了方便查找.

clc,
clear all;
close all;
format long;
% line: a*x &＃43; b*y &＃43; c &＃61; 0; a &＃61; 1, b &＃61; -1; c &＃61; 0
a &＃61; 1;
b &＃61; -1;
c &＃61; 0;
x &＃61; linspace(-20,20,100);
y &＃61; x;figure;
plot(x,y);
hold on;point &＃61; [1.0,20.0];
distance &＃61; abs(a*point(1) &＃43; b*point(2) &＃43; c)/sqrt(a^2.0 &＃43; b^2.0);
scatter(point(1),point(2));xlim([-21 21]);
ylim([-21 21]);
axis equal;
disp([&＃39;distance:&＃39; num2str(distance)]);