Question

Determine as soma dos trinta primeiros termos da P.A(3,5,7...)​

Answer 1

Explicação passo-a-passo:

an= ?

a1= 3

r= 2

n= 30

$an = a1 + (n - 1) \times r \\ an = 3 + (30 - 1) \times 2 \\ an = 3 + 29 \times 2 \\ an = 3 + 58 \\ an = 61$

$s = \frac{(a1 + an) \times n}{2} \\ s = \frac{(3 + 61).30}{2} \\ s = \frac{64.30}{2} \\ s = \frac{1920}{2} \\ s = 960$