User Christian Blatter - Mathematics Stack Exchange

167 votes

Accepted

Connection between Fourier transform and Taylor series

answered Oct 20, 2010 at 15:52

165 votes

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Intuitive interpretation of the Laplacian Operator

answered Jul 8, 2011 at 8:44

101 votes

20 circles in the plane, all passing through the origin

answered Feb 16, 2017 at 9:16

93 votes

Is there a clever solution to Arnold's "merchant problem"?

answered Nov 17, 2020 at 16:22

86 votes

What should be the intuition when working with compactness?

answered Feb 25, 2015 at 19:48

67 votes

What does the term "undefined" actually mean?

answered Apr 10, 2015 at 14:55

67 votes

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What is the remainder when $6^{273} + 8^{273}$ is divided by $49$?

answered May 8, 2021 at 9:29

64 votes

Is there a vector space that cannot be an inner product space?

answered Nov 29, 2012 at 19:31

62 votes

Is math built on assumptions?

answered Nov 5, 2013 at 16:56

55 votes

What is the limit of $n \sin (2 \pi \cdot e \cdot n!)$ as $n$ goes to infinity?

answered Nov 16, 2014 at 18:50

55 votes

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Representing the multiplication of two numbers on the real line

answered May 1, 2012 at 11:48

53 votes

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Appropriate Notation: $\equiv$ versus $:=$

answered Aug 13, 2012 at 16:03

52 votes

New Idea to prove $1+2x+3x^2+\cdots=(1-x)^{-2}$

answered Jul 28, 2015 at 20:09

49 votes

Nice proofs of $\zeta(4) = \frac{\pi^4}{90}$?

answered Mar 21, 2011 at 17:43

47 votes

What is the importance of the Collatz conjecture?

answered Aug 18, 2010 at 13:13

47 votes

Determine whether $f(x)={\sin x \over x}$ is uniformly continuous in $\mathbb R$

answered Jul 5, 2013 at 16:00

44 votes

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Mean Value Theorem for complex functions?

answered Oct 7, 2012 at 9:45

43 votes

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Is 1100 a valid state for this machine?

answered May 2, 2012 at 15:34

42 votes

Nice expression for minimum of three variables?

answered Jul 26, 2011 at 10:57

41 votes

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Formal basis for variable substitution in limits

answered Jul 7, 2012 at 18:19

41 votes

Do there exist pairs of distinct real numbers whose arithmetic, geometric and harmonic means are all integers?

answered Apr 16, 2018 at 10:51

39 votes

Is there any way to define arithmetical multiplication as other thing than repeated addition?

answered May 9, 2015 at 19:09

37 votes

Accepted

Prove that $\sqrt{7}^{\sqrt{8}}>\sqrt{8}^{\sqrt{7}}$

answered Jun 28, 2013 at 14:17

36 votes

Why should the substitution be injective when integrating by substitution?

answered Aug 18, 2013 at 13:33

36 votes

Why is the Möbius strip not orientable?

answered Dec 28, 2010 at 19:39

35 votes

Accepted

Every harmonic function is the real part of a holomorphic function

answered Feb 11, 2012 at 14:22

35 votes

Why do units (from physics) behave like numbers?

answered Oct 22, 2016 at 16:04

34 votes

Is there an elegant bijective proof of $\binom{15}{5}=\binom{14}{6}$?

answered May 24, 2017 at 8:00

34 votes

How is the angle between 2 vectors in more than 3 dimensions defined?

answered Jul 23, 2011 at 13:57

34 votes

What is the exact and precise definition of an ANGLE?

answered Nov 27, 2013 at 12:42

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7,022 Answers

Connection between Fourier transform and Taylor series

Intuitive interpretation of the Laplacian Operator

20 circles in the plane, all passing through the origin

Is there a clever solution to Arnold's "merchant problem"?

What should be the intuition when working with compactness?

What does the term "undefined" actually mean?

What is the remainder when $6^{273} + 8^{273}$ is divided by $49$?

Is there a vector space that cannot be an inner product space?

Is math built on assumptions?

What is the limit of $n \sin (2 \pi \cdot e \cdot n!)$ as $n$ goes to infinity?

Representing the multiplication of two numbers on the real line

Appropriate Notation: $\equiv$ versus $:=$

New Idea to prove $1+2x+3x^2+\cdots=(1-x)^{-2}$

Nice proofs of $\zeta(4) = \frac{\pi^4}{90}$?

What is the importance of the Collatz conjecture?

Determine whether $f(x)={\sin x \over x}$ is uniformly continuous in $\mathbb R$

Mean Value Theorem for complex functions?

Is 1100 a valid state for this machine?

Nice expression for minimum of three variables?

Formal basis for variable substitution in limits

Do there exist pairs of distinct real numbers whose arithmetic, geometric and harmonic means are all integers?

Is there any way to define arithmetical multiplication as other thing than repeated addition?

Prove that $\sqrt{7}^{\sqrt{8}}>\sqrt{8}^{\sqrt{7}}$

Why should the substitution be injective when integrating by substitution?

Why is the Möbius strip not orientable?

Every harmonic function is the real part of a holomorphic function

Why do units (from physics) behave like numbers?

Is there an elegant bijective proof of $\binom{15}{5}=\binom{14}{6}$?

How is the angle between 2 vectors in more than 3 dimensions defined?

What is the exact and precise definition of an ANGLE?