User contributions
- 05:54, 3 July 2008 (diff | hist) . . (+765) . . N KGS math club/solution 4 1 (New page: (a²+b²)(c²+d²) = (ac-bd)²+(ad+bd)² and (a1²+a2²+a3²+a4²)(b1²+b2²+b3²+b4²)= (a1b1 - a2b2 - a3b3 - a4b4)² + (a1b2 + a2b1 + a3b4 - a4b3)² + (a1b3 - a2b4 + a3b1 + a4b2)² + (...) (current)
- 16:36, 30 June 2008 (diff | hist) . . (+161) . . N KGS math club/solution 3 1 (New page: the distance between the origin and a center of a little sphere is sqrt(n). => The radius of the big sphere is sqrt(n)-1 So we must have sqrt(n)-1 <= 2, or n<=9)
