How to correctly plot a perpendicular on a point of a line in MATLAB? - MATLAB爱好者论坛-LabFans.com

poster · 2019-11-26, 09:20

I am trying to plot a perpendicular at the endpoint of a line in MATLAB. However, I don't think the angle between these two lines is 90 degrees. I know points x1, y1, x2, y2, then

plot([x1 x2],[y1 y2],'r'); hold on; grid on 

p = polyfit([x1 x2], [y1 y2], 1); % get line parameters 

m = p(1);  % get slope 

m=-1/m;        % calculate perpendicular slope



y=-55.5:0.02:-54.8;    

x=x1+((y-y1)./m); 

plot(x,y,'g'); 

axis square;

However, in the plot, it does not show 90 degree angle. What am I doing wrong here. Thanks.

2019-11-26, 09:20	#1
poster 高级会员注册日期: 2019-11-21 帖子: 3,006 声望力: 66	How to correctly plot a perpendicular on a point of a line in MATLAB? I am trying to plot a perpendicular at the endpoint of a line in MATLAB. However, I don't think the angle between these two lines is 90 degrees. I know points x1, y1, x2, y2, then `plot([x1 x2],[y1 y2],'r'); hold on; grid on p = polyfit([x1 x2], [y1 y2], 1); % get line parameters m = p(1); % get slope m=-1/m; % calculate perpendicular slope y=-55.5:0.02:-54.8; x=x1+((y-y1)./m); plot(x,y,'g'); axis square;` However, in the plot, it does not show 90 degree angle. What am I doing wrong here. Thanks. More answer...