How do you use the geometric sequence of numbers 1, 2, 4, 8,…to find r, the ratio between 2 consecutive terms?

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Answer 1 · 2015-11-05T19:46:56

$r = 2$
See explanation.

Let any term in a geometric sequence be $a$

Let the i'th term be $a_i$

Let a constant be k

Let the geometric ratio be r

The $a_i = kr^i$

$a_1 = kr = 1$
$a_2=kr^2 = 2$
$a_3 = kr^3=4$

So $a_(i+1)/a_(i) = (kr^(i+1))/(kr^i) = r$

So $a_2/a_1 = 2/1 =r=2$