User Joonas Ilmavirta

72 votes

Accepted

Notation: Vector contains an element equal to 0

answered Mar 28, 2018 at 12:24

64 votes

Why did no student correctly find a pair of $2\times 2$ matrices with the same determinant and trace that are not similar?

answered Apr 10, 2017 at 5:55

38 votes

What is the smallest unknown natural number?

answered Jun 7, 2015 at 12:04

34 votes

Is there a symbol for "taking a derivative of something"?

answered May 16, 2017 at 20:58

33 votes

Relation between the roots of a function

answered Feb 21, 2018 at 14:20

29 votes

Why there is no sign of logic symbols in mathematical texts?

answered Jul 21, 2015 at 9:17

28 votes

What does the symbol nabla indicate?

answered Mar 27, 2018 at 17:20

21 votes

Accepted

What is the difference between a generalization and an extension?

answered Apr 20, 2017 at 23:35

21 votes

Simple theorems that are instances of deep mathematics

answered Apr 5, 2017 at 3:29

20 votes

Accepted

Use of approximation sign

answered Aug 2, 2017 at 12:35

19 votes

Accepted

Are Vector Spaces over non-commutative fields ever studied?

answered Jul 7, 2015 at 20:47

19 votes

How to show that a given function is a polynomial?

answered Nov 24, 2017 at 6:49

18 votes

Is a map that preserves lines and fixes the origin necessarily linear?

answered Nov 29, 2016 at 9:14

17 votes

Accepted

Calculating $\ln(1+\sqrt3)$

answered Aug 10, 2014 at 20:52

16 votes

What is the position of the surviving mouse?

answered Apr 5, 2017 at 23:00

16 votes

What is the difference between "infinitely many $n$" and "large enough $n$"?

answered Jul 16, 2017 at 13:36

15 votes

I'm trying to find the longest consecutive set of composite numbers

answered Jun 6, 2017 at 17:56

13 votes

What is the length of a point on the real number line?

answered Sep 22, 2016 at 14:04

12 votes

Accepted

Lebesgue integral of Dirac delta

answered Jul 21, 2015 at 17:15

12 votes

Accepted

Outcome of rolling a fair die 6 times

answered Jul 30, 2014 at 20:12

12 votes

Accepted

Help evaluating triple integral over tetrahedron

answered Sep 7, 2014 at 20:21

11 votes

Accepted

If the derivative is zero on [a, b], then the function is constant - using Heine-Borel?

answered Jul 3, 2015 at 22:49

11 votes

Accepted

The limit of complex sequence

answered Aug 15, 2014 at 14:00

11 votes

Accepted

Matrix-version of $\frac1a+\frac1b=\frac{a+b}{ab}$?

answered Aug 18, 2014 at 12:49

11 votes

Notation for an interval when you don't know which bound is greater

answered Jun 9, 2018 at 17:46

10 votes

Accepted

Intuition behind eigenfunctions of the Laplacian operator

answered Jul 3, 2015 at 22:30

10 votes

Accepted

Is there a function that doesn't have a limit at infinity but its derivative does?

answered Jul 9, 2015 at 13:07

10 votes

Accepted

If $f$ is continuous and piecewise $C^1$ and $f'$ is bounded a.e., is $f$ Lipschitz?

answered Jul 9, 2015 at 14:00

10 votes

Show that trace is a unique linear functional

answered Jul 13, 2015 at 6:32

10 votes

Help me visualize a function with infinitely many logarithms of absolute values of logarithms

answered Jun 18, 2017 at 20:17

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434 Answers

Notation: Vector contains an element equal to 0

Why did no student correctly find a pair of $2\times 2$ matrices with the same determinant and trace that are not similar?

What is the smallest unknown natural number?

Is there a symbol for "taking a derivative of something"?

Relation between the roots of a function

Why there is no sign of logic symbols in mathematical texts?

What does the symbol nabla indicate?

What is the difference between a generalization and an extension?

Simple theorems that are instances of deep mathematics

Use of approximation sign

Are Vector Spaces over non-commutative fields ever studied?

How to show that a given function is a polynomial?

Is a map that preserves lines and fixes the origin necessarily linear?

Calculating $\ln(1+\sqrt3)$

What is the position of the surviving mouse?

What is the difference between "infinitely many $n$" and "large enough $n$"?

I'm trying to find the longest consecutive set of composite numbers

What is the length of a point on the real number line?

Lebesgue integral of Dirac delta

Outcome of rolling a fair die 6 times

Help evaluating triple integral over tetrahedron

If the derivative is zero on [a, b], then the function is constant - using Heine-Borel?

The limit of complex sequence

Matrix-version of $\frac1a+\frac1b=\frac{a+b}{ab}$?

Notation for an interval when you don't know which bound is greater

Intuition behind eigenfunctions of the Laplacian operator

Is there a function that doesn't have a limit at infinity but its derivative does?

If $f$ is continuous and piecewise $C^1$ and $f'$ is bounded a.e., is $f$ Lipschitz?

Show that trace is a unique linear functional

Help me visualize a function with infinitely many logarithms of absolute values of logarithms