Error using FEVAL Produced on an Attempt at calling fplot

I'm a beginner to MATLAB and i'm doing a practice assignment in my textbook which literally gives me each command to run and i'm still getting errors so I think it might have to do with my textbook being outdated. The following are the commands;

a = 123 * 2 * pi / 360;

L = inline('9 / sin(pi - 2.1468 - c) + 7 / sin(c)');

fplot(L, [0.4, 0.5]); grid on

This is the error produced after the fplot() function;

Error using feval Undefined function 'ezfcnchk' for input arguments of type 'inline'.

There are a few more lines of errors that I can provide if needed. Any advice helps, thanks in advance.

Answer 1

[Karan Gill]

First, a side note that you should format code in your posts: https://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup#answer_18099

Your textbook is quite outdated because "inline" isn't recommended anymore. You can check by looking up the "inline" page here: https://www.mathworks.com/help/matlab/ref/inline.html . There's a compatibility note at the top.

Following the note's recommendation, use an anonymous functions instead.

   L = @(c) 9/sin(pi-2.1468-c)+7/sin(c);

Does it work?

[mitchell rifkind]

It worked! Many thanks.