Example of Symbolic Expression
When there is more than one variable, the MATLAB selects which to solve for. In the illustration below, the equation ax^{2} + bx = 0 is solved. There are three variables. Since it can be seen from the result, that is given in terms of a and b, the equation was solved for x. The MATLAB has rules built in that to identify how to select which variable to solve for. For illustration, x will always be the first preference if it is in the expression or equation.
>> solve('a*x^2 + b*x')
ans =
0
-b/a
Though, it is possible to identify which variable to solve for:
>> solve('a*x^2 + b*x','b')
-a*x