Hey everybody:
I'm rather new to matlab so I'm sure this question isn't too difficult to solve, so bear wtih me. I would like to solve a quartic equation for a single variable  straightforward enough. However, the coefficients of this quartic are themselves functions. The actual equations are rather complicated, so I'll post a simplified example:
solve('a*x^4 + a*b*x^3 + c*x^2 + d = 0', 'x');
where
a = 4*m^3;
b = 3*sqrt(a*n);
c = 16*m*n;
d = 5*n^2;
where m and n are userdefined inputs.
As I understand it, solve only works when the input terms are cast as symbolic variables. However, whenever I try to cast a, b, c, d, m, and n as symbolic variables, neither values nor functionality is preserved. My question is, what needs to be defined as a symoblic variable, or is there another way to do this?
Thanks for your help.
am
