AngouriMath

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SolveByRationalisingASumOfRoots​(AngouriMath.​Entity,​AngouriMath.​Entity.​Variable,​System.​Boolean)

 Method (no overloads)

Summary

A denominator factor that is a sum or difference of two square roots of
polynomials, multiplied above and below by its conjugate:
(1 + x)/(sqrt(x^2 + 2x + 4) - sqrt(x^2 + x + 1)) is
(1 + x)(sqrt(x^2 + 2x + 4) + sqrt(x^2 + x + 1))/(x + 3), the product of the
pair being the difference of the radicands -- and each of the two terms is then a
root of a quadratic beside a rational function, Euler's. Timofeev's.

Remarks

Two roots only: a polynomial beside one root, x + sqrt(x^2 + 1), is Euler's
substitution itself, and answered more shortly as that. The conjugate is nonzero
wherever the factor is, and (a - b)(a + b) = a^2 - b^2 holds for the
principal roots as for any values, so nothing is assumed about signs. Once: the
respelling has no such factor left.
https://github.com/asc-community/AngouriMath/issues/718

























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