In a geometric sequence, t1 + t2 + t3 = 21 and t4 + t5 + t6 =168. Find the sequence.
how do u use the formula Sn = a(r^n -1)/r -1) to find the sequence?
Hellp, megs_world!
In a geometric sequence: .
Find the sequence.
how do u use the formula: to find the sequence?
We know the sum of the first 3 terms: .
. . Hence: . .[1]
We know the sum of the first 6 terms: .
. . Hence: . .[2]
Divide [2] by [1]: .
Factor and reduce: .
. . Then: .
Substitute into [1]: .
Therefore, the sequence is: .