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bio website hermanschaaf.com
location South Africa
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seen Jan 18 '13 at 8:51

King of the tumbleweed questions.


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comment Estimating a certain row of Pascal's triangle
@Rasmus: That is indeed very rough. Since we know the row adds up to $2^n$, can we make a better estimate for every number at position $i$ from knowing what percentage (approximately) that number should be making of the total?
Oct
14
comment Estimating a certain row of Pascal's triangle
Well, considering that the answer to Stirling's formula is several 100-1000s digits long, it takes a few milliseconds to calculate. That's not the bottleneck though, it is the multiplication and division of such large numbers that are taking really long. Maybe there's some way to speed that up in the code?
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asked Estimating a certain row of Pascal's triangle
Oct
14
comment How to solve an inequality containing the sum of factorials and powers
Sorry, that formula was meant to be: $-a(x+k)^k + \sum\limits_{j=0}^{y}x^{j}\binom{k}{k-j} \leq 0$
Oct
14
comment How to solve an inequality containing the sum of factorials and powers
By simple variable substitution I've managed to reduce the formula to the following: $-a(x+k)^k + \sum\limits_{j=0}^{y}x^{j}\bigl(\frac{k}{k-j}\bigr) \leq 0$. This seems right in the domain of root finding, I see.
Oct
14
comment How to solve an inequality containing the sum of factorials and powers
I've finally been able to get the book, Numerical Recipes, but since I'm new to the field, would you mind pointing me to the appropriate chapter for this kind of problem? Is it the chapter on root finding?
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accepted How to simplify or calculate a formula with very big factorials
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