Problem in using coeffs in a file

I am using Matlab mobile (Android), version 4.2.0.

I am creating a function, in which I am using the coeffs function. I want to extract the coefficients of x and y from an expression and use them elsewhere.

Say, my expression is x - y. If I use coeffs function in the command line, I get back an array, which is what I want. The code has been attached in the screenshot.

The command line gives me just what I want. But when I try do do the same from a file, an error comes up. See the other screenshot attached. In the second screenshot, plot2d is the function I have written, and eqn2 is the expression in which I want to find the coefficients of x and y. The line in the function is simply:

coeffs(eqn2,x)

I must add here that if I put the coeffs function in a different file and call that file, it works fine.

Any help is appreciated.

[Walter Roberson]

Please show your code for plot2d

[Wrichik Basu]

Thank you, but I've found my mistake.

[Kevin Chng]

What is the errors you found? Have a nice day.

[Wrichik Basu]

When I was using coeffs(eqn2,x), there was some value stored in x already, which was causing the problems.

[Kevin Chng]

Okay. great.....thanks for your sharing

Answer 1

[Kevin Chng]

Hi Wrichik Basu,

Do you mind to share your equation 2 here? Your error could be similar to case as below:

https://www.mathworks.com/matlabcentral/answers/49879-coeffs-of-non-linear-product-terms

[Wrichik Basu]

eqn2 depends on on the values of X and Y. But it is always a linear expression in x and y. You can take anything as eqn2. It has the form Ax + By + C, where A, B and C are constants.