I am trying to simplify a large symbolic expression and am running into a problem.
The problem is represented by the following code:
syms a b x
f = a*x + b*x + a*b*x*x
subs(f,a+b,'c')
subs(collect(f,x),a+b,'c')
Here, I see two different behaviors from subs. In the first, the substitution of a+b with c is ignored and the original expression is returned. In the second, the desired behavior occurs and the resulting expression replaces a*x+b*x with c*x. Is there something I am missing -- how can I get the first subs to work?
In a related issue, I am finding that the follwing code yields baffling results:
isequal(f,f)
isequal(f,collect(f,x))
The first equality check returns true -- as expected since f should equal itself. However, the second equality check returns false. Is this expected behavior, and if so, how does someone check for equality between expressions?
