Arithmetic Sequence
Has a common difference.
The below has a common difference of 4:
\$3,7,11,15,19,23,27\$
Find Specific Index
\$a_{n} = a_{1}+(n-1)d\$
Find Partial Sum
\$Sn = (\frac{a_{1}+a_{n}}{2})n\$
Geometric Sequence
Has a common ratio.
The below has a common ratio of 2:
\$3,6,12,24,48,96,192\$
Find Specific Index
\$a_{n} = a_{1}(r)^(n-1)\$
Find Partial Sum
\$Sn = \frac{a_{1}(1-r^n)}{1-r}\$