Question

1). which best describes the sequence below1.2, 0.36, 0. 108, .0324A). NeitherB). ArithmeticC). Geometric2). Write the explicit formula of an arithmetic sequence given the information below:a18 = 142 and a32 = 240

Answer 1

a = first term = 1.2

Therefore,

$\begin{gathered} nthterm=ar^{n-1} \\ 1.2\times r=0.36 \\ r=\frac{0.36}{1.2} \\ r=0.3 \\ \\ r=\frac{0.108}{0.36}=0.3 \\ r=\frac{0.0324}{0.108}=0.3 \end{gathered}$

The common ratio is 0.3. Therefore, it is a geometric sequence.

Note r = common ratio