Question

Find the 15th term of the geometric sequence 180, 90, 45,...

Answer 1

Answer:

$\frac{45}{4096}$

Step-by-step explanation:

1) q=90/180=45/90=...=1/2;

2) the formula of the n-th term of the given sequence is:

$a_n=a_1*q^{n-1};$

3) according to the formula 15th term is:

$a_{15}=a_1*q^{15-1}=180*\frac{1}{2} ^{14}=\frac{180}{16384} =\frac{45}{4096}$

or ≈0.011.