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

 Method (no overloads)

Summary

A power that is not whole of a rational function of one exponential, W = B(t)^p with
t = e^(s x), beside a polynomial in x whose coefficients are rational in t, by the ansatz
F = W P/(t^m E): P a polynomial in x and t of unknown coefficients, and E read
off the denominator of the rest, R = f/W. Rubi's 6.7.1
sqrt(csch(x)) (x cosh(x) - 4 sech(x) tanh(x)) is
(2 x/sqrt(csch(x)) - 4 sech(x)/csch(x)^(3/2))', sqrt(csch(x)) times a rational
function of x and e^x. By parts leaves -2/sqrt(csch(x)), which is elliptic, and so is
the other term, and the split declined them both.

Remarks

W'/W = p s t B_t/B is rational in t, so F' = W R is
(P/(t^m E))' + p s t (B_t/B) P/(t^m E) = R, a polynomial identity in x and t over one
denominator, linear in the unknowns. By Liouville's theorem an elementary antiderivative with no
logarithmic part is W times a rational function of x and t, with a denominator free of x, as R's
is, and a degree in x no higher than R's: a higher coefficient would be a constant over W, which
is not rational. Its denominator is R's with each factor's power lowered by one, or R's itself,
with t to any power, as SolveByRischNormanAnsatz(AngouriMath.Entity,AngouriMath.Entity.Variable) bounds its own.
W is the integrand's own power, and every other power of its base is written as W times a whole
power of the base, which holds on every branch: B^r = B^p B^(r - p) for a whole
r - p. Respelled in powers of the hyperbolic sine, sqrt(1/S) as 1/sqrt(S), the
same integrand was right only where sinh(x) > 0. Last, at the question asked, and checked
by its derivative.
https://github.com/asc-community/AngouriMath/issues/718

























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