If $1, \frac{1}{2}, \frac{1}{4}, \frac{1}{8}, \ldots$ is a G.P then $\mathrm{t}_{\mathrm{n}}=$ $\_\_

Question

If $1, \frac{1}{2}, \frac{1}{4}, \frac{1}{8}, \ldots$ is a G.P then $\mathrm{t}_{\mathrm{n}}=$ $\_\_\_\_$

Professor PC Thomas Classes · Answer

First term $a=1$, ratio $r=1/2$. $t_n = a r^{n-1} = 1 \cdot (1/2)^{n-1} = 2^{1-n}$.