The first two terms of a geometric sequence are a1 = 1⁄3 and a2 = 1⁄6. What is a8, the eighth term?

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Answer 1 · 2016-08-12T15:04:32

Use the formula $t_n = a xx r^(n - 1)$

Let's first find the value of $r$ , the common ratio.

$r = t_2/t_1$

$r = (1/6)/(1/3)$

$r = 1/6 xx 3$

$r = 1/2$

Now we can us the formula.

$t_n = a xx r^(n - 1)$

$t_8 = 1/3 xx (1/2)^(8 - 1)$

$t_8 = 1/8 xx 1/128$

$t_8 = 1/1024$

Hopefully this helps!