Biz \(L\) ni hisoblashimiz kerak.

\[L = \mathop {\lim }\limits_{n \to \infty } \sqrt[n]{{\left| {{a_n}} \right|}} = \mathop {\lim }\limits_{n \to \infty } {\left| {{{\left( {\frac{{3n + 1}}{{4 - 2n}}} \right)}^{2n}}} \right|^{\frac{1}{n}}} = \mathop {\lim }\limits_{n \to \infty } \left| {{{\left( {\frac{{3n + 1}}{{4 - 2n}}} \right)}^2}} \right| = {\left( { - \frac{3}{2}} \right)^2} = \frac{9}{4}\]

2-qadam

OK, biz \(L = \frac{9}{4} > 1\) va shunga o'xshash seriyani Root Test orqali ko'rishimiz mumkin farqlanadi.