Question

Determine the 8th term in the geometric sequence whose first term is -10 and whose common ratio is 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=-10\\ r=2\\ n=8 \end{cases} \\\\\\ a_8=-10\cdot 2^(8-1)\implies a_8=-10\cdot 2^7 \\\\\\ a_8=-10\cdot 128\implies a_8=-1280`