Question

find the nth term of each geometric sequence.
a1=2,n=4,r=-2
explain this please.

Answer 1

so if a = 2, r = -2, the sum for a geometric series is a/1-r, this tells you the form of the series \[\sum_{}^{}ar^n\]. so then you plug in your values, and have \[\sum_{0}^{\infty}-4^n\], so the 4th term is -4^4.