Question Number 131159 by mohammad17 last updated on 02/Feb/21
![](https://www.tinkutara.com/question/18460.png)
Commented by mohammad17 last updated on 02/Feb/21
![who can solve this ?](https://www.tinkutara.com/question/Q131160.png)
$${who}\:{can}\:{solve}\:{this}\:? \\ $$
Commented by mohammad17 last updated on 02/Feb/21
![chouse the right answer](https://www.tinkutara.com/question/Q131161.png)
$${chouse}\:{the}\:{right}\:{answer} \\ $$
Commented by EDWIN88 last updated on 02/Feb/21
![a_n = (((2n+3)!)/((n+1)!)) = (((2n+3)(2n+2)!)/((n+1)!)) =](https://www.tinkutara.com/question/Q131163.png)
$${a}_{{n}} =\:\frac{\left(\mathrm{2}{n}+\mathrm{3}\right)!}{\left({n}+\mathrm{1}\right)!}\:=\:\frac{\left(\mathrm{2}{n}+\mathrm{3}\right)\left(\mathrm{2}{n}+\mathrm{2}\right)!}{\left({n}+\mathrm{1}\right)!} \\ $$$$\:\:\:\:\:=\: \\ $$