Question
In GP the Eleventh term is 128 times the fourth term,and the sum of second term and third term is 6. Find:
1) Common ratio.
2)Sum of the first five terms
1) Common ratio.
2)Sum of the first five terms
Answers
Reiny
the Eleventh term is 128 times the fourth term
--> ar^10 = 128(ar^3)
divide by ar^3
r^7 = 128
r = 2 , so we already know the common ratio
the sum of second term and third term is 6
---> ar + ar^2 = 6
we know r, just complete to solve for a
--> ar^10 = 128(ar^3)
divide by ar^3
r^7 = 128
r = 2 , so we already know the common ratio
the sum of second term and third term is 6
---> ar + ar^2 = 6
we know r, just complete to solve for a