Use sigma notation (Σ) to represent a sum, e.g. and

The table below shows the number of visitors, \(v_i\), (in hundreds) to a wildlife sanctuary in week \(i\), where \(i = 1, 2, 3, \ldots, 8\). Write an expression using sigma notation (\(\Sigma\)) that represents the total number of visitors across all eight weeks, then calculate this total. Express your final answer in standard form.

A sequence is defined by \(u_n = 3n^2 - 2n + 5\) for \(n \geq 1\). (a) Determine the sum of the first 15 terms of this sequence, \(\sum_{n=1}^{15} u_n\). (b) Hence determine the value of \(\sum_{n=6}^{15} u_n\).

Which expression in sigma notation represents the sum \(3 + 6 + 12 + 24 + 48 + 96\)?