How to factor out several variables in a big equation?

Dear community, I have a very big equation (almost 1000 terms) with several variables I'm interested in. Let's call those x1, x2, x3, x4, x5 and so on. What I'd like to do is to factor out those variables - all at a time. This should be easy because the variables are linearly independent. The equation should look something this: x1(...) + x2(...) + x3(...) + x4(...) + x5(...) + ... = RHS. So, I would simply like to collect all the coefficients for the different variables. Normally, I would do it by hand but in this case that would be way too much work. Likewise, the susceptibility to errors would be too high... Can anybody help me with this? I cannot tell MATLAB what to do. I have the whole equation as a symbolic expression and tried collect() and factor() which didn't seem to do the trick. Ultimately I want to build up a system of linear equations which can be solved numerically later on. This however shouldn't be a problem once I have the upper representation of the equation. Thanks for your help!

Answer 1

[Toby Howison]

Use:

collect(expression, [x1,x2,x3,etc..])

But copy your expression into MuPad and use that environment, I had the same problem.

[Chris]

Thanks! It worked like a charm :)

[Tom Teasdale]

Thanks a lot!