There’s nearly a limitless amount of standard and well-defined functions with a single usage, like those. There’s hardly a point in implementing them in the standard library and C++ is the only language that I’m aware of that has those.

If the goal was to create a specialized library for solving differential equations, those would be handy there. But if not, even if you tried implementing everything that you could potentially think of to implement, there are hundreds of things that are orders of magnitude more useful to have and equally well-defined and standardized—even if we limit ourselves to mathematics alone, I’d much rather see basic constants like π or e included, or quaternions, or arbitrary precision integers, or decimal numbers… or dozens upon dozens of other things before that.

But mainly, I find it impossible to maintain the claim that any general-usage language, like C++, that implements such niche functions is trying to keep its standard library small and ‘include only elements that have a somewhat settled, "obvious", lowest-common-denominator semantics’.