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 Yearling
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Jan
17
asked Question about a lemma on continuity
Jan
8
comment Given the cartesian coordinates of four points, how to calculate the interection of two lines they form?
@J.M. Oh yeah. That looks good. THank you! BTW, is there a solution that use the $r,\vartheta$ representation instead?
Jan
8
comment Given the cartesian coordinates of four points, how to calculate the interection of two lines they form?
@J.M. Of course. This possibility is ruled out.
Jan
8
asked Given the cartesian coordinates of four points, how to calculate the interection of two lines they form?
Jan
1
awarded  Yearling
Dec
18
revised Find function if known some limit
Formatting
Dec
18
suggested approved edit on Find function if known some limit
Dec
8
awarded  Nice Question
Dec
2
comment Defining division by zero
@picakhu You are going to run into problems when calculating limits. Just consider $\lim_{n\to0}\frac{2n}n$. Using your method, one gets $\frac{\infty_0}{\infty_0}=1$, while one gets $\frac21=2$ using the definition of limits.
Nov
22
accepted Complexity of sorting algorthms
Nov
22
asked Complexity of sorting algorthms
Nov
22
answered Solve $f(f(n))=n!$
Nov
13
comment How to convert $\sqrt{\frac{5}{3}}$ to $\frac{\sqrt{15}}{3}$?
@Max ${5\over3}\to{15\over9}$
Nov
13
comment How to convert $\sqrt{\frac{5}{3}}$ to $\frac{\sqrt{15}}{3}$?
BTw, you can use LaTeX makeup by starting with an \$ and ending with another \$, for instance $\sqrt{\frac{5}{3}}$ becomes $\sqrt{\frac{5}{3}}$.
Nov
13
answered How to convert $\sqrt{\frac{5}{3}}$ to $\frac{\sqrt{15}}{3}$?
Nov
11
accepted A lemma of convergence
Nov
11
comment A lemma of convergence
@André: yes. We already proved that.
Nov
11
asked A lemma of convergence
Nov
8
comment The Mathematics of Tetris
That's an interesting question! I don't see any special reason for this, though.
Nov
1
comment Prove the identity $ \sum\limits_{s=0}^{\infty}{p+s \choose s}{2p+m \choose 2p+2s} = 2^{m-1} \frac{2p+m}{m}{m+p-1 \choose p}$
Hm... I recall that or a similar identity from Concrete Mathematics... maybe I find it again.