What is the formula for an arithmetic series? Geometric series? Arithmetic sequence? Geometric series?

Guest Mar 23, 2018

#2**+2 **

Here they are anyways:

Finding the n^{th} term: A_{n }= A_{1 }+ d * (n - 1)

S_{n} = (n/2)*(A_{1 }+ A_{n})

d is the common difference, A_{n} is the n^{th} term, A_{1} is the first term.

supermanaccz
Mar 23, 2018

#3**+2 **

For geometric series, there are many difference formulas to find the sum.

For infinite geometric series, those that don't have an end, (A_{1})/(n-1)

For those that do have an end, S_{n }= [A_{1}(1-r^{n})]/(1-r)

r is the common ratio, A_{1 }is the first term and n is the nth term.

To find the nth term:

A_{n} = AR^{n-1}

supermanaccz
Mar 23, 2018