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

The exponential substitution makes of Rubi's 6.7.1 1/(b cosh(x) + c sinh(x) + sqrt(b^2 - c^2))^4 the quotient 256 u^7/(u ((b - c)/(b + c) + 2 sqrt(b^2 - c^2)/(b + c) u + u^2))^4, whose
quadratic is (u + sqrt(b^2 - c^2)/(b + c))^2: its discriminant is
4 (b - c)/(b + c) - 4 (b^2 - c^2)/(b + c)^2, zero only once the root is squared and the
quotients are put over one bar, which the simplification does not do. Read as a quadratic
to the fourth power, the Hermite reduction solved for its numerators with the symbols in
every entry and declined after twenty seconds, and the table answered a piecewise of 6,557
characters on that discriminant, 53 GB in all; over the eighth power of the linear it is a
polynomial over a power of one linear, 416 characters in a second. The identity holds wherever A is not
zero, which a quadratic's leading coefficient is not. Only where the simplifier does not see
the zero, since the rules read that square already.
https://github.com/asc-community/AngouriMath/issues/233