Find a G.P. for which sum of the first two terms is `- 4` and the fifth term is 4 times the third term.

Explanation

given that ,`a+ ar=-4` eqn(1)

`T_5 = 4T_3`

`ar^4 = 4ar^2`

`r^2=4`

`r= +-2`

now `a(1+r)= -4`

if `r=2, a= -4/3`

`-4/3 + (-8/3)+ (-16/3) ........`

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