Recent content by Jay1

Yes, I noticed. It's amazing some of the math that far predates calculators and modern computation methods. I often marvel at what they could do in the ancient past and I still use concepts developed by ancient Greeks to develop my programs today. Imagine what Newton or Einstein could have...

Interesting. Apparently I stand corrected. A book I have shows various methods of testing divisibility, but they skip 7 and say no specific method exists other than trial and error. But that book dates back to the 1970s, when the Earth was young, we were on the verge of another ice age and...

You insert LaTeX code verbatim like this using CODE and /CODE tags enclosed within square brackets. Everything between the tags will be listed verbatim. $$X = \sum_{n=0}^5\left(\left(\sum_{j=1}^k A_{X,n,j} \cdot {cos(B_{X,n,j} + t \cdot C_{X,n,j})}\right) \cdot t^n\right)$$ which...

As I understand it, a specific test for divisibility by 7 has not yet been discovered. Where's Fermat when we need him?

PHP has some powerful arbitrary-precision (BC or binary calculator) arithmetic functions which seem to be greatly underused and only consist of the basic arithmetic operations, a square root function, a mod function and an integer power function. However, those basic operations can be used to...