Square-root of a matrix
6:05
Prove a^2 + b^2 + c^2 is at least ab + bc + ca for real numbers
20:10
Where did this come from?
21:39
a * b = ab + a + b
16:47
Prove that n^3 +11n is divisible by 6
16:40
Number of digits of n!
13:33
Ancient trick to calculate ANY square root
17:50
1973 USAMO ( System of equations)
18:08