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2.29.3  Exact values of rational roots of a polynomial :
rationalroot

rationalroot takes 1 or 3 arguments : a polynomial and optionnally two reals numbers α,β.

To find the rational roots of 2*x3−3*x2−8*x+12, input:

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

Output :

[2,3/2,-2]

To find the rational roots of 2*x3−3*x2−8*x+12 in [1;2], input:

rationalroot(2*x^3-3*x^2-8*x+12,1,2)

Output :

[2,3/2]

To find the rational roots of 2*x3−3*x2+8*x−12, input:

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

Output :

[3/2]

To find the rational roots of 2*x3−3*x2+8*x−12, input:

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

Output :

[3/2]

To find the rational roots of (3*x−2)2*(2x+1)=18*x3−15*x2−4*x+4, input:

rationalroot(18*x^3-15*x^2-4*x+4)

Output :

[(-1)/2,2/3]

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