
Re: get coefficients from a symbolic polynomial
Posted:
Jan 5, 2013 5:02 PM


On 1/5/2013 3:49 PM, Qiming wrote: >
> Hi Nasser: > > Thanks for your reply. > > In your case, actually only 'x' is symbolic, the coefficients 0,1,2,3 are already >in numerical form. But my question is: what if 0,1,2,3 are all in symbolic forms? > > I only give a simple example so that you might think why can't I >directly put 0,1,2,3 in the expression. However, in my real application, >those coefficients long and complicated and are generated by MATLAB symbolic >tool box. I just want to "retrieve" those coefficients for my future use. Of >course I can check those coefficients from the command window, but I >don't want to put them back in my code by hand. > > Qiming >
why is it so hard for someone to just make a simple example to explain what they mean? one spends so much time writing words, instead of making a simple code example.
If you mean this:
EDU>> syms x a b EDU>> y=a*x^2+b*x+1;
then do
EDU>> coeffs(y,x) [ 1, b, a]
If you still mean something else, then make up a small example. Do not explain in words, show a small Matlab example of the input polynomial itself. complete and self contained example. I am sure you can make one up if you try.
Nasser

