Sigma Notation

You can express the summation of some number of terms of a sequence using sigma or summation notation.

This notation follows the pattern

\[ \sum^{x}_{n = 0} 2n + 1 \]

Where \( x \) is the end term of the summation and \( n \) is the start term - which can be set to anything using the \( = \) and it is followed by a definition of the sequence.

So, if we wanted to get summation of term \( 10 \) to \( 20 \) of the sequence \( 2n + 1 \) we would write it as

\[ \sum^{20}_{n = 10} 2n + 1 \]