The sum of an indicated number of terms in a sequence is called series, for example, the sum of the first seven terms of the sequence {n²} is the series

First seven series {n²} ppt:

1+4+9+16+25+36+49.

Above series is also name as the 7th sum of series {n²}

Finite series:

If the number of term in a series is finite, then the series is called finite series,

Infinite series :

While a series consisting of an unlimited number of terms is termed as an infinite series.

Sum of first n terms of an arithmetic series:

For any sequence we have

If is an A. P, then can be written in the form

….. A

If we write the term of the series in the reverse order,