Question

Find T4, T7 and T9 for each of the following geometric progressions :3, 6,12,24

Answer 1

$$t_1=3, t_2=6, t_3=12, t_4=24$$

Common ratio $r=\dfrac{t_2}{t_1}=\dfrac{t_3}{t_2}=\dfrac{t_4}{t_3}=2$

$$t_4=24$$

$$t_7=t_1\cdot r^6=3\cdot 2^6=192$$

$$t_9=t_1\cdot r^8=3\cdot 2^8=768$$