Question

determine o número de termos da PA 1/3, 1/6..... -8/3​

Answer 1

para visualizar a resposta acesse

https://brainly.com.br/tarefa/31976836

$\sf{a_1=\dfrac{1}{3}}\\\sf{r=\dfrac{1}{6}-\dfrac{1}{3}=-\dfrac{1}{6}}\\\sf{a_n=-\dfrac{8}{3}}\\\sf{a_n=a_1+(n-1)r}\\\sf{n=\dfrac{a_n-a_1}{r}+1}\\\sf{n=\dfrac{-\frac{8}{3}-\frac{1}{3}}{-\frac{1}{6}}}\\\sf{n=\dfrac{-3}{-\frac{1}{6}}+1}\\\sf{n=3\cdot6+1}\\\huge\boxed{\boxed{\boxed{\boxed{\sf{n=19}}}}}$