Question

5: Find the sum of first 24 terms of the list of numbers whose nth term is
3 + 2n​

Answer 1

$an = a + {{n - 1}d$

$an \: is \: arthmatic \: progressin$

$a1 = 3 + 2n$

$a1 = 3 + 2$

$a1 = 5$

$a2 = 3 + 2{2$

$a2 = 7$

$d = a2 - a1$

$d = 7 - 5$

$d = 2$

$sn \: = \frac{n}{2} \times 2a \: + {n - 1}d$

$s24 = \frac{24}{2} \times 2(5) + (24 - 1)2$

$s24 = 12((10 + 23)2)$

$s24 = 12(33 \times 2)$

$s24 = 12 \times 66$

$s24 = 792$