Which term of the GP is -128?

Given GP is ….


The given GP is of the form, a, ar, ar2, ar3….


Where r is the common ratio.


The first term in the given GP,


The second term in GP,


Now, the common ratio,



Let us consider -128 as the nth term of the GP.


Now, nth term of GP is, an = arn – 1


n – 1


2)n = 1024 = (-2)10


n = 10


So, -128 is the 10th term in GP.


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