Label Root of Function on Graph - Matlab Help

[.ryan.]

Hey guys. Can someone help me with the syntax needed to label the root of a function on a graph, using Matlab? I've used the help function, but I couldn't find anything that was effective. Thanks.

 

[LeBrad]

Hey guys. Can someone help me with the syntax needed to label the root of a function on a graph, using Matlab? I've used the help function, but I couldn't find anything that was effective. Thanks.

I'm not sure if there's a way to make Matlab find and label roots on a plot, but you can make it find them separately and plot that point on the plot.

For example, if you are plotting y vs. t and want to find the roots of y, you can do
roots = find(abs(y)<=eps)
(or roots = find(abs(y) == min(abs(y))) if you know there's only one root). This finds the indices in the y vector corresponding to (approximately) the roots of y.

Then you can do
plot(t,y,t(roots),y(roots),'*');label('y','roots')
to plot y vs. t, and then on top of that it plots stars on the points where you found roots. There may be better ways but that's the best thing I can think of off hand.

 

[tacman]

Sure, I'd be happy to help. To label the root of a function on a graph using Matlab, you can use the "text" function. The syntax for this function is "text(x,y,'label')", where x and y are the coordinates of the point you want to label and 'label' is the text you want to display. So, for example, if your root is located at (2,0), you can use the following code:

text(2,0,'root')

This will place the label "root" at the point (2,0) on your graph. I hope this helps! Let me know if you have any further questions.