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University of Florence


10h
revised How to find $F(x) = \int_x^{x^2} (2+\sqrt t )\, dt$ ?
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10h
comment How to find $F(x) = \int_x^{x^2} (2+\sqrt t )\, dt$ ?
Write the intermediate passages
Sep
15
comment existence of a differentiable function under certain given condition
The requirements on $f(0)$ and $f'(0)$ don't mean anything. Maybe it was $x=0$?
Sep
15
comment Constructing a circle from a square
The example you found is exactly a proof that perimeter is not continuous. And when I speak of "metric" I mean a distance between sets, not points. There is no such a think like Euclidean metric on the family of sets. Look for example at en.wikipedia.org/wiki/Hausdorff_distance
Sep
15
revised Constructing a circle from a square
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Sep
15
answered Constructing a circle from a square
Sep
15
comment Ellipsoidal Decomposition: Finding ellipsoids whose sum contains a given ellipsoid
You mean: the union of these two ellipsoids encloses $E$? But the union of them will not be an ellipsoid...
Sep
12
reviewed Approve suggested edit on Order of error of a fraction
Aug
27
answered How to graph functions without a calculator?
Aug
27
revised Verify my proof: If $X$ is infinite, then there exists $f: \mathbb{N} \rightarrow X$ such that $f$ is injective.
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Aug
27
comment Verify my proof: If $X$ is infinite, then there exists $f: \mathbb{N} \rightarrow X$ such that $f$ is injective.
@Guilherm: I cannot understand your proof. Seems you are saying: take the function $f$ such that the maximal set where $f$ is injective, is maximal. It's not clear at all how you can define such things. Take $f(n)=\lfloor n/2\rfloor$ and explain what is $k$ for such a function. Also the notation $a \neq b \neq c$ is bad, don't use it.
Aug
26
answered Verify my proof: If $X$ is infinite, then there exists $f: \mathbb{N} \rightarrow X$ such that $f$ is injective.
Aug
26
answered Is the dot product valid for coordinate vectors of infinite length?
Aug
26
revised Can I conjugate a complex number: $\sqrt{a+ib}$?
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Aug
26
answered Can I conjugate a complex number: $\sqrt{a+ib}$?
Aug
26
revised Can I conjugate a complex number: $\sqrt{a+ib}$?
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Aug
26
answered Computing $\sum_{i=0}^{\infty}\frac{i}{2^{i+1}}$
Aug
26
revised Min and max of a product.
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Aug
26
revised Min and max of a product.
added 722 characters in body
Aug
26
answered Min and max of a product.