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 $a _ { 12 } \text { when } a _ { 1 } = - 4 , r = 2$
A) 18
B) -8,192
C) -16,384
D) -8,188

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, $a_{12} = -4 \cdot 2^{(12-1)} = -4 \cdot 2^{11} = -4 \cdot 2048 = -8,192$.

Use the Formula for the General Term (The Nth Term) a12 when a1=−4,r=2a _ { 12 } \text { when } a _ { 1 } = - 4 , r = 2a12​ when a1​=−4,r=2

Use the Formula for the General Term (The Nth Term) $a _ { 12 } \text { when } a _ { 1 } = - 4 , r = 2$