What is the value of #-1.5- 3- 6- 12...,# for #n = 7#?

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Answer 1 · 2018-01-16T23:08:08

#-96#

This is a geometric series. The common ratio is:

#(-3)/(-1.5)=(-6)/(-3)=2#

The nth term of a geometric series is given by:

#ar^(n-1)#

Where a is the first term, r is the common ratio and n is the nth term.

From example:

#a=-1.5#

#r=2#

#n=7#

#:.#

#-1.5*2^6=-1.5*64=-96#