AngouriMath

Navigation

← Back to list of members

SolveByTheMoebiusSubstitutionOfAQuotientOfLinears​(AngouriMath.​Entity,​AngouriMath.​Entity.​Variable)

 Method (no overloads)

Summary

A power of a quotient of two linears beside whole powers of the two, under the Moebius
substitution t = (p + q x)/(r + s x): then p + q x = t (r + s x),
r + s x = D/(q - s t) and dx = D/(q - s t)^2 dt with D = q r - p s, so
t^alpha (p + q x)^j (r + s x)^k dx is D^(j + k + 1) t^(alpha + j) (q - s t)^(-(j + k + 2)) dt,
a polynomial in t times a power of it wherever j + k <= -2. A whole power of
a quadratic that is a multiple of the two linears' product counts as a power of each.
e^(n acoth(a x)) arrives folded as ((a x + 1)/(a x - 1))^(n/2), and over
(c - a^2 c x^2)^m it is Rubi's 7.4.2.
https://github.com/asc-community/AngouriMath/issues/233

Remarks

Only for a power alpha that is not whole: a whole one makes a rational function,
which the partial fractions answer. t^gamma is differentiated to
gamma t^(gamma - 1) t' on the principal branch wherever t is not 0, the
negative half-line included, so the answer written back in the quotient holds where
the integrand is defined. A half-odd power of the quadratic is left alone: it is not
the product of the linears' powers on every side of their roots.

























Angouri © 2019-2023 · Project's repo · Site's repo · Octicons · Transparency · 4862 pages online