- #1
chikis
- 237
- 1
Homework Statement
How many terms
has the G.p whose
2nd term is 1/2
and common ratio
and the last term
1/4 and 1/128
respectiveley?
From the question, it can be deduced that the common ratio, r =1/4 and the last term = 1/128
Homework Equations
The Nt term of a G.p =
arn-1
The Attempt at a Solution
Given that r, the
common ratio=1/4.
T2, the second
term is =1/2.
Using the formula
arn-1
where a = first
term and r is =
common ratio.
Thus:T2=a(1/4)2-1
=1/2
a(1/4) = 1/2
a/4 = 1/2
2a = 4
a = 4/2
a = 2
Recall that Tn of
G.p = arn-1
To find the Nt
term, we need to put a, r and the last term in equation
arn-1 = 1/128
2(1/4)n-1 =1/128
I multiplied through
by 1/2
2 * 1/2(1/4)n-1 =
1/128 * 1/2
(1/4)n-1 = 1/256
I don't know how
to deal with the
power n-1 in other
to procceed
further and arive
at the answer.
Last edited: