error in disp line

the following error appears in the code and it shows a figure with no lines.

[Sulaymon Eshkabilov]

Where are your sol variable values? Where and how have you computed them that is not visible from your given screenshot? As is shown here, you have not solved the equations and thus, you've got this error.

[Walter Roberson]

It looks to me as if you used to have a call to solve() that is not there any more.

Caution: your Theta is only two values, so each of your plot elements only joins two locations in a straight line. I suspect you are thinking that [0 120] is telling it to calculate for the entire range 0 to 120, but that is not the case in this context: it means only 0 and 120 exactly

Answer 1

[DGM]

First off, use the formatting tools available to you to post the actual code. Do not post pictures of code. Nobody can run a picture of code.

What is sol? How did a0, a1, etc suddenly become elements of sol?

Perhaps change the line to reflect the variables that exist.