Question

dada progressão aritmética 4 8 12 calcule:

Answer 1

A progressão está sendo feita de 4 em 4, continue:

4,8,12,16,20,24,28,32,36...

Answer 2

Bom dia João!

Solução!

$a1=4\\\\\ r=a2-a1\\\\\ r=8-4\\\\ r=4$


$a_{40}=a1+39r\\\\\\ a_{40}=4+39(4)\\\\\\ a_{40}=4+156\\\\\\ a_{40}=200$

$\boxed{Resposta:a_{40}=200}$

$a1=-8\\\\ r=a2-a1\\\\\ r=16-(-8)\\\\\ r=16+8\\\\ r=24\\\\\\ n=30\\\\\\ an=-8+29r\\\\\ an=-8+29.(24)\\\\ an=-8+696\\\\ an=688$

$S_{n}= \dfrac{(a1+an).n}{2} \\\\\ S_{n}= \dfrac{(-8+688).30}{2} \\\\\ S_{n}= \dfrac{(680).30}{2} \\\\\ S_{n}= \dfrac{(20400).30}{2} \\\\\ S_{n}= 10200$

$\boxed{Resposta:S_{n}= 10200}$











Bom dia!
Bons estudos!