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Roots

The command allroots functions with variable coefficients also, but only, if the polynomials degree in the main variable is smaller than 3, or it is biquadratic. If roots of other variables x are searched, one should use the more general solve(p,x), which will be discussed in more detail later.
>> syms x,z
>> y = x*z^2-3*x*z+(2*x+1);
>> allroots(y)
ans = [ sqrt((1/4*x-1)/x)+3/2  -sqrt((1/4*x-1)/x)+3/2 ]
>> solve(y,x)
ans = -1/(z^2-3*z+2)


Helmut Dersch
2009-03-15