How to correctly plot a perpendicular on a point of a line in MATLAB?
 

<p>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</p>

<pre><code>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;
</code></pre>

<p><a href="https://i.stack.imgur.com/ZNTYc.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZNTYc.png" alt="enter image description here"></a></p>

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



[url=https://stackoverflow.com/questions/59042351/how-to-correctly-plot-a-perpendicular-on-a-point-of-a-line-in-matlab]More answer...[/url]