Question

Use sigma notation to represent the sum of the first eight terms of the following sequence: 4, 7, 10, …

Answer 1

Answer:

$\displaystyle \boxed{ \sum_{k=1}^{8} (1+3k) }$

Step-by-step explanation:

Hello,

We are looking for something like

$\displaystyle \sum_{k=1}^{8} u_k$

where

$u_1=4\\ \\u_2=7 \\ \\u_3 =10 \\ \\u_k=1+3k$

So,

$\displaystyle \sum_{k=1}^{8} u_k=\sum_{k=1}^{8} (1+3k)\\\\=\sum_{k=1}^{8} (1)+3\sum_{k=1}^{8} (k)\\\\=8+3\times \dfrac{9*8}{2}\\ \\=8+108=116$

Thanks