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12238
bio website math.ntnu.no/~hanche
location Trondheim, Norway
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visits member for 2 years, 9 months
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39m
comment gamma function in $c^{2}$
You should go for $C^1$ first. Try to write up the definition of the derivative, and see if you can move the limit operation inside the integral. Or did you try that already?
51m
comment Lebesgue Measure: No Atoms!
I added an explanation.
51m
revised Lebesgue Measure: No Atoms!
Add some detail
1h
comment Lebesgue Measure: No Atoms!
My answer could be a different way.
1h
answered Lebesgue Measure: No Atoms!
9h
comment Determining whether a set is open and bounded
If $g$ and $h$ are continuous on $[a,b]$, then they are bounded. You can easily get a bound for your set from that.
9h
comment Determining whether a set is open and bounded
I am pretty sure the word you are looking for is “bounded”. A variable is typically called constrained if it is required to take values in some subset, for example given by an equation $f(x)=0$, but you rarely (if ever) call a set constrained.
1d
comment prove that $\sup\frac{1}{A}=\frac{1}{\inf A}$
It's false if $A=(-1,0)\cup(0,1)$. Besides, you forgot a sup in the final line, not to mention you have not showed us what you have tried.
1d
answered Explicit formula for the implicit Euler method
1d
comment Explicit formula for the implicit Euler method
I think whoever posed the question only wants you to write an explicit formula for $y_{n+1}$ in terms of $y_n$, not an explicit formula in terms of $n$ and the initial data, which is much harder. But if I'm right, this should have been stated more clearly.
1d
comment Explicit formula for the implicit Euler method
My guess: You write up the formula for implicit Euler and try to solve it for $y_{n+1}$. You get a quadratic equation, so you have to pick one of its roots. That is where the consistency comes in.
1d
comment Limit problem involving cosine
$-|x|^3\le x^3\cos(\text{anything real})\le|x|^3$. Seriously.
1d
comment Can a Norm be Induced by two Different Complex Inner Products?
The point @DanielFischer is making is that the polarization identity lets you reconstruct any inner product from the norm that it defines. So if two inner products define the same norm, the two inner products must be the same.
2d
comment closed but not exact
Nothing wrong with your attempt, until the final sentence. You do have a contradiction, because $\theta$ is not well defined single valued continuous function.
2d
answered Why limit $\sqrt{\frac{\sin(x)}{x}}$ as $x \rightarrow \infty$ is not a real number?
2d
comment Modular Arithmetic Root
With a bit of luck, $97+101k$ is a perfect cube for some smallish $k$.
2d
comment How can I calculate this limit without using L'Hopital's rule?
Somewhat less whimsically, you can use the Taylor expansions of the numerator and denominator to get the limit.
2d
comment How can I calculate this limit without using L'Hopital's rule?
A somewhat whimsical comment: Any limit calculation using L'Hôpital can be done without it, but there is a risk that the resulting calculation essentially duplicates the proof of L'Hôpital in a special case.
Oct
20
comment Why is there two versions of the rotation matrix?
@joeA Yes, that is not unlikely.
Oct
20
answered Well-ordered set with greatest element is compact