l want to know the arithmetic progression formulae

• September 1st 2012, 10:22 PM
kshai215
l want to know the arithmetic progression formulae
my name is kabir and I am studying XI science I want to formulae of arithmetic progression.
• September 1st 2012, 10:26 PM
Prove It
Re: l want to know the arithmetic progression formulae
\displaystyle \begin{align*} t_n = a + (n-1)d \end{align*} and \displaystyle \begin{align*} S_n = \frac{n}{2}[2a + (n-1)d] \end{align*} or \displaystyle \begin{align*} S_n = \frac{n}{2}( a + l ) \end{align*}.