sequence+series
sequence
series
infinite
finite
list of numbers
when we add terms of sequence
arithmetic
increase by the same amount every term
nth term
\(a+(n-1)d\)
d=difference
arithmetic
number of terms*average of 1st and last term
first n numbers
\(\frac{n(n+1)}{2}\)
sum of first n odd integers \(n^2\)
geometric
common ratio between terms
\(n^{th}\) term
\(ar^{n-1}\)
geometric
sum: n. terms, first term a and common ratio r
\(\frac{a(r^n-1)}{r-1}\)
infinite geometric series
\(\frac{a}{1-r}\)