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132108
bio website math.ethz.ch/~blatter
location Switzerland
age 78
visits member for 3 years, 11 months
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Jul
1
answered Why Fourier transform owns two different signs?
Jun
30
comment Existence of Riemann Integral
Concerning "I do not wish to use continuity": Do we have to introduce $\sin$ from first principles, e.g., prove that it satisfies a Lipschitz condition?
Jun
30
comment Characterization of differentiable functions from $\mathbb{R}^m$ to $\mathbb{R}^n$.
The formula in my answer and the statement in your comment are equivalent.
Jun
30
answered A proof (result) verification of a statement in metric-spaces
Jun
30
answered Application of Liouville's theorem exercise
Jun
29
comment Why is the symbol ζ sometimes used in a complex function?
When studying functions of one real variable one uses $x$, $t$, or $r$ (and other letters) as names for the independent variable. In the same way one uses $z$, $\zeta$, or $w$ (and other letters) as names for a complex independent variable.
Jun
29
answered Characterization of differentiable functions from $\mathbb{R}^m$ to $\mathbb{R}^n$.
Jun
28
answered Heat Equation derivative in terms of Laplace
Jun
28
revised points with integer coordinates inside triangles in $\Bbb{R}^3$
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Jun
28
revised How find this maximum of the $\sin^2{\theta_{1}}+\sin^2{\theta_{2}}+\cdots+\sin^2{\theta_{n}}$
added 78 characters in body
Jun
28
answered points with integer coordinates inside triangles in $\Bbb{R}^3$
Jun
27
comment Drawing the longest line segment contained in an area
Note that the length of the maximal segments is well defined; but there can be many such maximal segments, as in the case of a regular polygon or a circle. This makes it difficult to set up an algorithm for finding such a segment.
Jun
27
revised How find this maximum of the $\sin^2{\theta_{1}}+\sin^2{\theta_{2}}+\cdots+\sin^2{\theta_{n}}$
added 349 characters in body
Jun
27
revised How find this maximum of the $\sin^2{\theta_{1}}+\sin^2{\theta_{2}}+\cdots+\sin^2{\theta_{n}}$
added 68 characters in body
Jun
27
answered How find this maximum of the $\sin^2{\theta_{1}}+\sin^2{\theta_{2}}+\cdots+\sin^2{\theta_{n}}$
Jun
26
answered fitting rectangle inside another rectangle in diagonal
Jun
25
revised L. Kronecker's theorem for sequences and series: $\lim_{n\to\infty}\frac{1}{b_n}\sum_{k=1}^na_kb_k=0$
edited title
Jun
25
answered Find the differential equation of all circles of radius 1 centered on the y-axis
Jun
25
comment Find the differential equation of all circles of radius 1 centered on the y-axis
These circles are centered on the $x$-axis. By the way: There is a typo in your second equation.
Jun
25
answered How to show if n is prime, then $\{1,2,…,n-1\}$ is a group?