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Robert Israel earned this badge 84 times |
may 12 at 17:01
Why $\displaystyle f(z)=\frac{az+b}{cz+d}$, $a,b,c,d \in \mathbb C$, is a linear transformation?
mar 15 at 21:10
What was the first bit of mathematics that made you realize that math is beautiful? (For children's book)
mar 15 at 11:05
Do people ever study non-commutative fields?
feb 23 at 2:49
$(1+\frac{1}{n\log n})^n-1=O(\frac{1}{n})$.
feb 21 at 2:40
Is the series $\sum \sin^n(n)$ divergent?
feb 8 at 15:17
How would one go about proving that the rationals are not the countable intersection of open sets?
jan 29 at 21:34
Is $\frac{1}{\exp(z)} - \frac{1}{\exp(\exp(z))} + \frac{1}{\exp(\exp(\exp(z)))} -\ldots$ entire?
jan 23 at 12:43
The last digit of $2^{2006}$
jan 7 at 23:43
Rational Roots of Riemann's $\zeta$ Function
jan 5 at 5:45
Eigenvalue of a matrix
dec 12 at 4:05
Why is $E(\min(A, B)) < \min(E(A), E(B))$?
oct 31 at 21:34
Ramanujan's approximation to factorial
oct 31 at 20:39
Properties of the number 50
oct 25 at 22:57
Is $n \sin n$ dense on the real line?
sep 11 at 9:41
Prove $ 1 + 2 + 4 + 8 + \dots = -1$
sep 3 at 20:43
Proving the identity $\sum\limits_{k=1}^n {k^3} = \left(\sum\limits_{k=1}^n k\right)^2$ without induction
aug 28 at 23:14
Showing that the image of a function is $\mathbb{C}$ if it satisfies a nice functional equation
aug 28 at 6:19
Is the statement “1/3 of the natural numbers are divisible by 3” true? Is anything similar to it true?
aug 14 at 8:43
On an Elementary Problem in Additive Number Theory
aug 7 at 0:23
“L'Hôpital's rule” vs. “L'Hospital's rule”?
aug 1 at 23:20
Are non-circular swords possible?
jul 31 at 4:24
Solving $5^n > 4,000,000$ without a calculator
jul 27 at 14:20
What's the analogue of Sierpinski triangle to disk?
jul 26 at 11:18
How to show that this set is compact in $\ell^2$
jul 19 at 14:26
Why does Maclaurin get his own polynomial?
jul 9 at 6:46
Help find hard integrals that evaluate to $59$?
jul 5 at 4:14
Some math symbols seem useless
jun 9 '12 at 3:25
Does there exist a 3-dimensional subspace of real functions consisting only of monotone functions?
jun 6 '12 at 11:19
How can we solve: $\sqrt{x} - \ln(x) -1 = 0$?
jun 3 '12 at 19:30
Arithmetic of irrationals and the Vedanta behind it..
may 22 '12 at 6:57
What is the larger of the two numbers?
may 21 '12 at 13:07
How come the Euclidian distance for n-space involves only squares?
may 19 '12 at 12:45
Predict next number from a series
may 18 '12 at 23:35
Approximation for $\pi$
may 13 '12 at 22:52
How many numbers of $8$ digits and $9$ digits are there which are multiples of $11$?
may 3 '12 at 23:50
Prime Number Generator: $n\cdot2^n - 1$?
may 2 '12 at 19:44
What are some examples of a mathematical result being counterintuitive?
apr 27 '12 at 23:47
How to prove that for $x$,$y$ positive if $x > y$, then $\frac{1+2x}{1+x} > \frac{1+2y}{1+y}$?
apr 17 '12 at 10:22
What does $2^x$ really mean when $x$ is not an integer?
mar 26 '12 at 13:04
A counterexample for Big Rudin's Chapter 3 Exercise 4
mar 7 '12 at 2:01
Simple but difficult to prove inequality involving integrals
feb 28 '12 at 14:46
Product of adjacency matrices
feb 18 '12 at 12:42
Is there an explicit isomorphism between $L^\infty[0,1]$ and $\ell^\infty$?
feb 14 '12 at 22:54
Is there a 'far' irrational number?
