Reputation
137,955
Next tag badge:
388/400 score
179/80 answers
Badges
10 133 265
Newest
 Nice Answer
Impact
~1.3m people reached

2d
answered Suppose $A$ is a subset of $B$ and $B$ is a subset of $C$ and $A$ is equinumerous with $C$. Prove $B$ is equinumerous with $C$.
2d
revised Suppose $A$ is a subset of $B$ and $B$ is a subset of $C$ and $A$ is equinumerous with $C$. Prove $B$ is equinumerous with $C$.
Adjust title to match body
2d
revised Suppose $A$ is a subset of $B$ and $B$ is a subset of $C$ and $A$ is equinumerous with $C$. Prove $B$ is equinumerous with $C$.
Adjust title to match body
2d
comment Find the smallest $N$ such that $\sum_{k=1}^N\frac{1}{p_k}>\pi$. (The $p_k$'s are the prime numbers.)
Just to put this in perspective: With $N=3260806$, we have $\log\log(\frac N{\log N}+1)-\log{\frac{\pi^2}6}\approx 2.01$, which is way off. To get anywhere near $\pi$, you'd need $N\approx 10^{18}$ and surely don't want to work backwards from there
2d
comment How can I find the radius and interval of convergece of $\sum_{n=0}^\infty {(x+5)^n} $, and for what value of x does the series converge?
also: root test
2d
revised Power to which 7 is raised to produce a number starting with 2015…
deleted 1 character in body
2d
answered question regarding group permutation computation
2d
comment Prove that $F=\left(-x^2+2\right)\cdot \cos\left(x\right)+2x\sin\left(x\right)$ don't have limit
@AndreiMihai Not even that (alos, $f$ and $F$ are not periodic strictly speaking). It is enough to have long enough intevals at hand where we can nicely estimate from below. Starting with the even more nonperiodic $f(x)=x^2\sin(x^2)$ the above method still leads to success.
2d
revised Power to which 7 is raised to produce a number starting with 2015…
added 1672 characters in body
2d
answered Power to which 7 is raised to produce a number starting with 2015…
2d
comment How calculate the probability that there is a row in which there is no silver coin?
How do governments enter this scene?
2d
revised Proof of linear independence of non-empty subsets
rolled back to a previous revision
2d
answered Proof of linear independence of non-empty subsets
2d
revised Proof of linear independence of non-empty subsets
rolled back to a previous revision
2d
revised Proof of linear independence of non-empty subsets
deleted 1 character in body
2d
revised Prove that $F=\left(-x^2+2\right)\cdot \cos\left(x\right)+2x\sin\left(x\right)$ don't have limit
added 10 characters in body; edited title
2d
answered Prove that $F=\left(-x^2+2\right)\cdot \cos\left(x\right)+2x\sin\left(x\right)$ don't have limit
2d
answered $\mathbb Q [\sqrt{2} i]$ contains neither $\sqrt[4]{2}$ nor $\sqrt{2}$
2d
answered What is the difference between these two conditions $J = \{az \mid a \in R\}$ and $ I = \{a \in R \mid az \in J\}$
2d
comment Are $x$ and $y$ divisible by $n$, if so how do I prove it?
If you know that how can you still ask whether $4\mid 6$ and $4\mid 2$ are true?