Phonon
  • Member for 10 years, 10 months
  • Last seen more than 2 years ago
6 answers
227 votes
291k views
180 bookmarks
Eigenvectors of real symmetric matrices are orthogonal
3 answers
20 votes
12k views
15 bookmarks
Probability, conditional on a zero probability event
3 answers
13 votes
2k views
19 bookmarks
A good book for learning mathematical trickery
4 answers
8 votes
5k views
3 bookmarks
Fun calculus problem I can't seem to solve
4 answers
6 votes
3k views
4 bookmarks
Infinite series expansion of $\sin (x)$
5 answers
6 votes
3k views
3 bookmarks
Algebraic proof that collection of all subsets of a set (power set) of $N$ elements has $2^N$ elements
2 answers
6 votes
11k views
5 bookmarks
Outer product of a vector with itself
6 answers
5 votes
4k views
4 bookmarks
Bernoulli's representation of Euler's number, i.e $e=\lim \limits_{x\to \infty} \left(1+\frac{1}{x}\right)^x $
1 answers
5 votes
293 views
1 bookmarks
Why generalize the derivative for multivariable functions?
2 answers
5 votes
324 views
Need help with very simple set theoretic proofs
1 answers
4 votes
1k views
Is there an intuitive interpretation of $ABA^T$?
3 answers
3 votes
813 views
Looking for an accessible explanation of Henstock–Kurzweil (gauge) integral
1 answers
3 votes
151 views
1 bookmarks
Series for reciprocal of polylogarithm?
1 answers
3 votes
201 views
Need help finding inverse under $a\circ b = a^b b^a$
2 answers
2 votes
282 views
Is inverse image of a point a set?
1 answers
2 votes
263 views
Need help demonstrating a property of bilinear forms
2 answers
2 votes
147 views
Finding, writing down and visualizing images of functions
1 answers
2 votes
380 views
1 bookmarks
State-space to transfer function
2 answers
2 votes
245 views
Z transform of a complex convolution
1 answers
1 votes
550 views
1 bookmarks
How is determinant defined by variable elimination?
0 answers
1 votes
71 views
Is there a name/notation for coordinate-wise identical function?
0 answers
1 votes
133 views
1 bookmarks
Finding inverse of a general linear transform
4 answers
1 votes
3k views
Notation for "all integers less than $n$"
1 answers
1 votes
32 views
If a set is not $G_\delta$ in a metric space, is it also not $G_\delta$ is a larger metric space?
1 answers
1 votes
60 views
Is there a name for this general problem (variation on least squares)?
0 answers
0 votes
110 views
Branch of mathematics that studies groups / rings or rational functions
1 answers
0 votes
77 views
Proving that a set is not $G_\delta$
2 answers
0 votes
104 views
Need help proving this linear inequality