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

 Method (no overloads)

Summary

A power of x times artanh(A x/sqrt(d + B x^2)) with A^2 = B, by parts:
the logarithm ln((1 + u)/(1 - u)) that artanh(u) is written as has the
derivative 2 u'/(1 - u^2), and for this u, 1 - u^2 = d/(d + B x^2) and
u' = A d/(d + B x^2)^(3/2), so it is 2 A/sqrt(d + B x^2). So
integral x^m ln(...) = x^(m + 1)/(m + 1) ln(...) - 2 A/(m + 1) integral x^(m + 1)/sqrt(d + B x^2),
for every whole m but -1. Rubi's 7.3.7, x^m artanh(sqrt(e) x/sqrt(d + e x^2)).
https://github.com/asc-community/AngouriMath/issues/233

Remarks

The search takes it by parts too, and differentiates the logarithm as written: a quotient
of two sums with a root in each, which it never brought down to the root alone, and the
remainder it asked about ran past the budget. The identity is algebraic, with no branch in
it: it holds wherever d is not 0 and the root is.

























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