There is a differentiable function from R to R that has a unique critical point that is a local maximum but still not have a global maximum?
33308
Unique local extremum is absolute extremum for continuous functions
120784
Differentiablility over closed intervals
34750
If every point is a local maximum, is it a step function?
152328
A continuously differentiable map is locally Lipschitz
43874
Differentiability implies continuity - A question about the proof
4084
Does there exist a holomorphic function with the following property?
155871
Is it possible for a function to be smooth everywhere, analytic nowhere, yet Taylor series at any point converges in a nonzero radius?
2506
twice differentiable functions
64197
Subgradients of non-convex functions
5295
Can the graph of a bounded function ever have an unbounded derivative?
38417
How to find the non-differentiable point(s) of a given continuous function?
18825
Integrable but not differentiable function
154572
Continuity of a function at an isolated point
132730
Is there an everywhere discontinuous increasing function?
95694
Is there a name for the function $\max(x, 0)$?
12556
A non-trivial, non-negative, function bounded below by its derivative with $f(0)=0$?
108997
Continuous functions that attain local extrema at every point