If the 2nd term of a Gp is 6 and the 4th term is 54,find the 1st term and the 5th term

4 answers

Let a be the first term and r be the common ratio respectively. Then

Second term of G.P. is

ar=4. (from the question) …1

4^(th) term of G.P. is

ar^3=64 (from question) …2

Divide 2 by 1

ar^3/ar =64/4

r^2 =16

r=4
not even close. Jeon!
r^2 = 54/6 = 9
r = ±3

a1 = a2/r
a5 = a4*r
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