Omnomnomnom
Reputation
73,572
293/400 score
5 48 96
Impact
~654k people reached

 62 Meaning of $\dfrac{x-y}{y}$ versus $\dfrac{x}{y}-1$ 42 A function f(x) that increases from 0 to 1 when x increases from 0 to infinity. 40 Why is the commutator defined differently for groups and rings? 31 Why is $1/i$ equal to $-i$? 30 Rigour in mathematics

### Reputation (73,572)

 +10 Find a matrix with determinant equals to $\det{(A)}\det{(D)}-\det{(B)}\det{(C)}$ +10 In a ring R, if there exists a in R s.t. ab=0 for any b in R, then a must be 0. Is this statement true? +15 how to estimate the eigenvalue of a covariance matrix? +15 Operatornorm of $(\mathbb{R}^d, \|\cdot\|_1) \to (\mathbb{R}^d, \|\cdot\|_{\infty})$

### Questions (27)

 12 Prove that if $f$ is continuous at $0$, it is continuous on $\mathbb{R}$ 11 Can the “inducing” vector norm be deduced or “recovered” from an induced norm? 11 How was the first log table put together? 11 Is there anything “nice” about the set of normal matrices (over $\Bbb R$ and $\Bbb C$?) 7 Prove that there exists a sequence $(x_n)$ such that $\sum_n a_n x_n$ diverges

### Tags (439)

 2k linear-algebra × 1433 282 algebra-precalculus × 69 1k matrices × 709 260 abstract-algebra × 138 570 real-analysis × 296 196 analysis × 100 494 calculus × 202 195 limits × 69 293 eigenvalues-eigenvectors × 194 185 functions × 66

### Accounts (16)

 Mathematics 73,572 rep 54896 English Language & Usage 136 rep 7 Physics 132 rep 6 Computational Science 111 rep 3 Stack Overflow 101 rep 2