Topic : GP

Q1. Find the GP for which the sum of the first two terms is -4 and the fifth term is 4 times the third term.

Asked by Pankaj | 7th Oct, 2018, 07:03: PM

Expert Answer:

First term = a
second term = ar
third term = ar2
fifth term = ar4
a+ar=-4
ar4=4ar2
r2=4
r=+2 or -2
a+a(2)=-4
3a=-4
a=-4/3..........r=+2 
 
a+a(-2)=-4
-a=-4
a=4...........r=-2 

Answered by Arun | 8th Oct, 2018, 12:14: PM