Question

What is a formula for the nth term of the given sequence?135, -225,375...

Answer 1

Step 1: Write out the formula for a geometric sequence

`\begin{gathered} T_n=ar^(n-1) \\ \text{Where} \\ T_n=\text{ the nth term} \\ a=\text{ the first term} \\ r=\text{ the common ratio} \end{gathered}`

Step 2: Write out the given values and find the formula

`\begin{gathered} a=135, \\ r=-(225)/(135)=-(5)/(3) \end{gathered}`

Therefore the formula is given by

`T_n=135(-(5)/(3))^(n-1)`

Hence, the correct choice is the first choice