English
If f and g are ContinuousWithinAt on s at x, then f/g is ContinuousWithinAt on s at x.
Русский
Если f и g непрерывны внутри s в точке x, то f/g непрерывно внутри s в x.
LaTeX
$$$\\mathrm{ContinuousWithinAt}(f,s,x) \\Rightarrow \\mathrm{ContinuousWithinAt}(g,s,x) \\Rightarrow \\mathrm{ContinuousWithinAt}\\bigl(x \\mapsto f(x)/g(x)\\bigr) s x$$$
Lean4
@[to_additive sub]
theorem div' (hf : ContinuousWithinAt f s x) (hg : ContinuousWithinAt g s x) :
ContinuousWithinAt (fun x => f x / g x) s x :=
Filter.Tendsto.div' hf hg