2,624 reputation
2033
bio website ephorie.de
location Germany
age 44
visits member for 4 years
seen yesterday

just an amateur fascinated by math


May
13
comment Example for finite dimensional analog of integral transforms
@MattL.: To be honest with you I don't know because I don't know the Z-transform well enough. But perhaps you could give an example that contains the elements I asked for in my question?
May
13
asked Example for finite dimensional analog of integral transforms
May
9
awarded  Notable Question
Apr
28
awarded  Nice Question
Apr
28
revised Intuition for complex eigenvalues
edited title
Mar
9
accepted Intuition and counterexamples for higher-order derivative test
Mar
8
comment Intuition and counterexamples for higher-order derivative test
I was just talking about your example: In our axiomatic system it is not defined at point $0$ because you are dividing by zero there! I am not talking about nature but only about things happening within the realms of pure maths. Yet could you give me a reference for the number of smooth functions and formulas accessible? Thank you again.
Mar
8
comment Intuition and counterexamples for higher-order derivative test
The intuition is appealing - thank you and +1! Considering your example: I disagree: It does not have a minimum at zero - it has literally nothing at zero because it is not defined there, neither are any of its derivatives (see also comments to my question).
Mar
8
comment Intuition and counterexamples for higher-order derivative test
Is it possible to find a counterexample where you don't have a separate case at the extreme value (as with this example at $0$)? This feels a little bit like cheating because the "original function" is not defined at this point.
Mar
8
comment Intuition and counterexamples for higher-order derivative test
Thank you Daniel: $x^{12}$ doesn't answer my question concerning an intuition. Even $x^4$ would work as an example, this is not the problem.
Mar
8
asked Intuition and counterexamples for higher-order derivative test
Feb
25
reviewed Approve suggested edit on How do I solve $y'=\frac{y}{x}\frac{x-y}{x+y}$?
Feb
25
reviewed Approve suggested edit on Integral equation and constant rules
Feb
25
reviewed Approve suggested edit on Factoring $x$ out of the denominator of a limit
Feb
25
reviewed Approve suggested edit on How come we ignore constants when finding derivatives?
Feb
16
reviewed Approve suggested edit on If a function $f$ is continuous in $[a,∞)$ and finite $\lim_{x→+∞}⁡f(x)$ exists, then it's uniformly continuous in $[a,+∞)$.
Feb
16
reviewed Approve suggested edit on If f: $[0,\infty)\to \mathbb{R}$ is continuous and uniformly continuous in $[k,\infty]$, then it's uniformly continuous in $[0,\infty]$.
Jan
27
reviewed Approve suggested edit on $n$ balls of $2^{n}-1$ colors, order not significant, how many combinations?
Jan
26
reviewed Approve suggested edit on Does this function define an inner product?
Jan
26
reviewed Approve suggested edit on A subgroup has the same number of left and right cosets - Tricks - Fraleigh p. 103 10.32, 35