The same plot in Mathcad will shows no apparent break @ 5.
Mathcad plots on ½ pica thus plots straight lines, thus not fine/pleasant look.
Smath plots on pixel thus the discontinuous were there is no ½ pixel.
A scalar function is a function that runs on a vanishing iterator 'x' .
Smath does not calculate ln(,), exp(,) ... it fetches from Windows.
Most if not all functions are approximations of 21 decimals.
i.e: Normalized Padé Rational Fractions.
Result may be only 18 Decimals. Thus, by convention results are
truncated to 15 decimals. Symbolic Engines is another story.
High accuracy Main-Frames may run Chebyshev of very high numerical
stability 25 decimals [typical Clenshaw ...]
Normalized Rational Fraction approximates on various best range wrt
to minimal arithmetic operations. Each function has its own specific range
generally very small. More numerical maths kind of scale the base range
to accommodate the 'x' of greater value than the base approximation,
naturally up to the max of the result < 10^307.
Before the event of rational approximations the first IBM used
continued fraction for the principal ln(x), exp(x), sqrt(x) ...
Can't help more about unknown math suite/use of the proposal.