Use the formula for the general term (the nth term) of a geometric sequence to find the indicated term of the sequence with the given first term, a1, and common ratio, r.
-Find $a _ { 6 }$ when $a _ { 1 } = 3200 , r = - \frac { 1 } { 2 }$.
A) 100
B) $- 100$
C) $- 50$
D) $- 10$

Question

Quizplus · Accepted Answer

The formula for the nth term of a geometric sequence is $a_n = a_1 \cdot r^{n-1}$. Plugging in the given values, $a_6 = 3200 \cdot (-\frac{1}{2})^{6-1} = 3200 \cdot (-\frac{1}{2})^5 = 3200 \cdot -\frac{1}{32} = -100$.

Use the Formula for the General Term (The Nth Term) a6a _ { 6 }a6​

Use the Formula for the General Term (The Nth Term) $a _ { 6 }$