Question

Find the common ratio of the infinite geometric series with the given sum and first term

S=18 , a (sub) 1 =12

Answer 1

use the formula
\(\huge S_\infty = \dfrac{a_1}{r-1} \)

Answer 2

i did but i cant get past the step to divide both sides by 10 .... i have examples in my book but its not varey informative

Answer 3

i mean 1-r

18 = 12/(1-r)

so,1-r = (12/18)

can you proceed?

Answer 4

yeah i got to the point where 1-r = 2/3