Question

What is the value of the fourth term in a geometric sequence for which a1 = 30 and r = 1/2?.

Answer 1

`\bf n^(th)\textit{ term of a geometric sequence}\\\\ a_n=a_1\cdot r^(n-1)\qquad \begin{cases} n=n^(th)\ term\\ a_1=\textit{first term's value}\\ r=\textit{common ratio}\\ ----------\\ a_1=30\\ r=(1)/(2)\\ n=4 \end{cases}\implies a_4=30\left( (1)/(2) \right)^(4-1)`