Question

What is the sum of the arithmetic series

Answer 1

Answer:

$S_ {12} = 192$

Step-by-step explanation:

The nth term of the given arithmetic sequence is

$U_n = 3 + 2n$

The first term of this series is:

$U_1 = 3 + 2(1) = 5$

The last term of this series is when

$n = 12$

$U_ {12}= 3 + 2(12)$

$U_ {12}= 3 + 24 = 27$

The sum of the first n terms of an arithmetic series when the first an last term is known is given by:

$S_n = \frac{n}{2}(a + l)$

Where a=5 is the first term and l=27 is the last term.

$S_ {12} = \frac{12}{2}(5 + 27)$

$S_ {12} =6(32) =19 2$