Question

Find sum of arithmetic series where a1 = 7, n=31, an=127

Answer 1

2077

Step-by-step explanation

To find the sum of an arithmetic sequence, use the formula

`\begin{gathered} S_n=n((a_1+a_n)/(2)) \\ \text{where} \\ n=the\text{ number of terms being added} \\ a_1=the\text{ firs term} \\ a_n=the\text{ nth term}(\text{ last term)} \end{gathered}`

Step 1

Let

`\begin{gathered} a_1=7 \\ n=31 \\ a_n=127 \end{gathered}`

now, replace and calculate

`\begin{gathered} S_n=n((a_1+a_n)/(2)) \\ S_n=31((7+127)/(2)) \\ S_n=31((134)/(2)) \\ S_n=31(67) \\ S_n=2077 \end{gathered}`

therefore, the answer is

2077

I hope this helps you