Question

Find the fifthterm in the geometricsequence, given the first term and the common ratioa1 = 5 and r = -3a5=?

Answer 1

Given: A geometric sequence with first term and the common ratio a1 = 5 and r = -3.

Required: Fifth term of the geometric series.

Step-by-step explanation:

In a geometric sequence, with first term 'a' and common ratio 'r'

nth term is

`a_n=ar^(n-1)`

So the fifth term is

`a_5=ar^4`

a = 5 and r = - 3.

So

`\begin{gathered} a_5=(5)(-3^)^4 \\ a_5=5(81) \end{gathered}`

So

`a_5=405`

Final Answer: The fifth term of Geometric sequence is 405.