Exact values of the complex rational roots of a polynomial : crationalroot

crationalroot takes 1 or 3 arguments : a polynomial and optionnally two complex numbers $\alpha$,$\beta$.

• If crationalroot has 1 argument, crationalroot returns the list of the complex rational roots of the polynomial without multiplicity.
• if crationalroot has 3 arguments, crationalroot returns only the complex rational roots of the polynomial which are in the rectangle with sides parallel to the axis having [$\alpha$,$\beta$] as opposite vertices.

To find the rational complex roots of (x² +4)*(2x - 3) = 2*x³ -3*x² + 8*x - 12, input :

crationalroot(2*x^3-3*x^2+8*x-12)

Output :

[2*i,3/2,-2*i]