Find a formula for the n th term of the geometric sequence. Assume that n begins with 1. $4,-10,25,-\frac{125}{2}, \ldots$
A) $a_{n}=2\left(-\frac{5}{2}\right)^{n-1}$
B) $a_{n}=2\left(-\frac{5}{2}\right)^{n-2}$
C) $a_{n}=4\left(-\frac{5}{2}\right)^{n-1}$
D) $a_{n}=-2\left(-\frac{5}{2}\right)^{n}$
E) $a_{n}=-4\left(-\frac{5}{2}\right)^{n}$

Question

Quizplus · Accepted Answer

The first term $a_1 = 4$, and the common ratio $r = \frac{-10}{4} = -\frac{5}{2}$. Thus, the formula for the nth term is $a_n = 4\left(-\frac{5}{2}\right)^{n-1}$.

Find a Formula for the N Th Term of the Geometric