Revision sheet · Mathematics

Sequences and series

Sum of the first n terms of a GP: $S = \frac{a ( r ^{n} - 1 )}{r - 1}$
Sum of an infinite GP: $S = \frac{a}{1 - r}$
Sum of the first n squares: $S = \frac{n ( n + 1 ) ( 2 n + 1 )}{6}$
Sum of the first n cubes: $S = (\frac{n ( n + 1 )}{2})^{2}$
The geometric mean of two numbers: $G = ab$