how to define a function

why do I have error message when I type

function dy = ff(t,y)

[Charles Kinoshita]

but shouldn't I be able to type

>> clear
>> function yprime = bvexample(t,y)
 function yprime = bvexample(t,y)
 ↑
Error: Function definitions are not permitted in this context.

[Steven Lord]

No. You cannot define functions by typing the text of their body at the Command Prompt. You need to write them as a function file. [If your function can be written as one statement, you could create an anonymous function handle.]

Answer 1

[James Tursa]

If you are getting this message:

Error: Function definitions are not permitted in this context.

It means that you cannot define a function in that part of the code. E.g., you cannot define functions at the end of script files in older versions of MATLAB. So either turn your script file into a function file itself, or copy your function code to a new file (with the name ff.m).

But this is all just a guess, since you haven't told us what the error message is or shown us any code.