Common factor

Is there a function to make it find a common factor in an expression with symbolic variables?

For example:

ab+ac--(matlab command)--->a(b+c)

Thanks

Answer 1

[Andrei Bobrov]

help factor

syms a b c
factor(a*c + b*c)

[cyberdyne]

I've tried that but it worked one time only....now returns me the error:

Error using==>subsindex

Function 'subsindex' is not defined for values of class 'sym'

How is it possible?

[Walter Roberson]

Did you happen to define a new factor.m ? Try

which factor

[cyberdyne]

No. The error returns if I use 'factor' funcion in command window while editor runs.

A bug?

[Walter Roberson]

I haven't heard of that one before. Does that include if the editor is up but showing no files at all ?

[Zoya Saevna]

You shouldn't be kidding!

[Steven Lord]

I know this part of the discussion is kind of old, but that error message cyberdyne quoted is likely to occur if for example the user were to store the output of the call to the factor function to a variable named factor in the Command Window. [Though it appears the text of the error message may have changed in the decade+ since the original message.]

syms a b c
f = a*b+a*c

f = 

factor = factor(f) % This first call works

factor = 

z = factor(f) % This second one does not, since factor is now a variable

Error using indexing (line 918)
Invalid MATLAB indexing or symbolic function definition. Symbolic function arguments must be symbolic variables and function body must be convertible to sym expression.

Error in indexing (line 962)
R_tilde = builtin('subsref',L_tilde,Idx);