Respostas

2013-08-08T16:57:33-03:00
O problema nos diz que:

a_1=-2\hspace{2.0cm}a_n=43\hspace{2.0cm}n=2+8=10

Utilizando a fórmula do termo geral, temos:

a_n=a_1+(n-1)r\\\\
43=-2+(10-1)r\\\\
45=9r\\\\
r=5

Agora podemos calcular os 8 números:

a_2=a_1+r\Longrightarrow a_2=-2+5=3\\\\ a_3=a_2+r\Longrightarrow a_3=3+5=8\\\\ a_4=a_3+r\Longrightarrow a_4=8+5=13\\\\ a_5=a_4+r\Longrightarrow a_5=13+5=18\\\\ a_6=a_5+r\Longrightarrow a_6=18+5=23\\\\ a_7=a_6+r\Longrightarrow a_7=23+5=28\\\\ a_8=a_7+r\Longrightarrow a_8=28+5=33\\\\ a_9=a_8+r\Longrightarrow a_9=33+5=38

Então podemos escrever a PA:

(-2,5,8,13,18,23,28,33,38,43)
3 5 3