How do you find $S_{n}$ $S_n$ for the arithmetic series given $a_{1} = 43$ $a_1=43$ , $a_{n} = 115$ $a_n=115$ and n=19?

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Answer 1 · 2016-10-15T13:44:29

$s_{19} = 1508$ $s_19 = 1508$

We can use the formula $s_{n} = \frac{n}{2} (t_{1} + t_{n})$ $s_n = n/2(t_1 + t_n)$ to find the sum.

$s_{19} = \frac{19}{2} (43 + 115)$ $s_19 = 19/2(43 + 115)$

$s_{19} = \frac{19}{2} (158)$ $s_19 = 19/2(158)$

$s_{19} = 1508$ $s_19 = 1508$

Hopefully this helps!

How do you find SnS_n for the arithmetic series given a1=43a_1=43, an=115a_n=115 and n=19?