Question

question
find the 12th term of the geometric sequence 5, 15, 45, ...
answer attempt 1 out of 2

Explanation:

Step1: Identify common ratio $r$

$r = \frac{15}{5} = 3$

Step2: Recall geometric term formula

The $n$-th term of a geometric sequence is $a_n = a_1 r^{n-1}$, where $a_1=5$, $n=12$, $r=3$.

Step3: Substitute values into formula

$a_{12} = 5 \times 3^{12-1} = 5 \times 3^{11}$

Step4: Calculate $3^{11}$ and final value

$3^{11}=177147$, so $a_{12}=5 \times 177147 = 885735$

Answer:

885735