2. What are series? Series are just terms of a sequence; you are just adding them up. For example 1+2+3+4+5+6…. is a series. This is just an easy series, a much more complicated series is ∑_(n=0)^∞▒x^n/n! which is a called a Taylor series. There are much more complicated series and are very useful in math, for example these series may be used to calculate pi or e. First we will take a look at all the series that converge to pi and we will classify them as either converging to pi fast or slow and why.
2.1 Series converging to pi
Gregory’s formula
The first formula ill look at is Gregory’s formula for pi, which was obtained by plugging 1 for x. Gregory’s formula states: equation (9) tan^(-1)1= 1-1^3/3+1^5/5-1^7/7+⋯ tan^(-1)1 That is just π/4
Thus Gregory’s formula π/4 =1-1^3/3+1^5/5-1^7/7+⋯
Machin’s formula
The first formula ill look at is the Machin’s formula, by John Machin and he computed pi to 100 decimal