Question
Show that the products of the corresponding terms of the sequences $\mathrm{a}, \mathrm{ar}, \mathrm{ar}^2$,............ $a r^{n-1}$ and $A, A R, A R^2$............. $A R^{n-1}$ form a G.P. and find the common ratio.

Answer

Multiplying the corresponding terms of the given sequences, we have$( a \times \mathrm { A } ) , ( a r \times \mathrm { AR } ) _ { : } \left( a r ^ { 2 } \times \mathrm { AR } ^ { 2 } \right),$........,$\left( a r ^ { n - 1 } \times \mathrm { AR } ^ { n - 1 } \right)$
$\Rightarrow(A),\left(a A r^R\right),\left(a A r^2 R^2\right), \ldots \ldots,\left(a A r^{n-1} R^{n-1}\right)$ are in G.P.
Now ${{{a_2}} \over {{a_1}}} = {{aArR} \over {aA}} = rR$ and ${{{a_3}} \over {{a_2}}} = {{aA{r^2}{R^2}} \over {aArR}} = rR$
Since the ratio of the two succeeding terms are same, the resulting sequence is also in G.P
and common ratio = $\frac { a \mathrm { A } r \mathrm { R } } { a \mathrm { A } } = r \mathrm { R }$​​​​​​​

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free