[tex]\begin{gathered} r=2\text{ common ratio} \\ a_n=a_1\cdot r^{n-1}_{} \\ \text{Substitute }n=4,\text{ and }r\text{ = 2} \\ a_n=a_1\cdot r^{n-1}_{} \\ a_4=2\cdot2^{4-1}_{} \\ a_4=2\cdot2^3 \\ a_4=16 \\ _{} \end{gathered}[/tex]
The first 4 terms therefore are, 2, 4, 8, 16.
