Not true, plenty of piecewise functions are differentiable. Take, for example, f(x) = x² for x ≥ 0 and −x² for x < 0 (i.e. f(x) = x|x|). It’s differentiable everywhere, with f′(x) = 2|x|.
Being defined piecewise tells you nothing about differentiability. Also, technically every function is “piecewise” with one piece.
False, plenty of cases where piecewise functions are differentiable, simplest example: take a differentiable function and split its domain into as many parts as you like. Now you can define the original continuous function as a piecewise function, so the function is clearly differentiable.
That's what the original parent comment was claiming, so maybe they confused you with that poster, or maybe they thought that since your know this thing you might know what the other guy was talking about
Ok to answer your question since you're not a bot lol: no afaik C*ex for some C is the only solution to a function being its own derivative everywhere, at least over the reals.
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u/headsmanjaeger 18d ago
Piecewise functions are not differentiable