robjohn
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# 199,967 Reputation

10 today
 +10 3 hours ago upvote Why is the inradius of any triangle at most half its circumradius?
70 yesterday
 +20 18:54 2 events Find the value of $\sum_{r=0}^{\left\lfloor\frac{n-1}3\right\rfloor}\binom{n}{3r+1}$ +10 23:22 upvote Odds of 10 thrown dice landing all the same +10 19:19 upvote Sign with Fourier transformation, convolution, periodicity +10 14:29 upvote Proving that ${x +y+n- 1 \choose n}= \sum_{k=0}^n{x+n-k-1 \choose n-k}{y+k-1 \choose k}$ +10 10:20 upvote Find the sum of $\sum 1/(k^2 - a^2)$ when $0 85 2 days ago  +35 08:18 3 events Proving that${x +y+n- 1 \choose n}= \sum_{k=0}^n{x+n-k-1 \choose n-k}{y+k-1 \choose k} $+10 20:40 upvote How many sides does a circle have? +10 15:50 upvote A trigonometric problem when calculating distance to the boundary of a convex hull +10 08:07 upvote A closed form for the infinite series$\sum_{n=1}^\infty (-1)^{n+1}\arctan \left( \frac 1 n \right)\$ +10 07:46 upvote what is maximum number of points of intersection between the diagonals of a convex octgon? +10 06:33 upvote How do you prove Gautschi's inequality for the gamma function?
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