Question

State and prove D' Alembert's Ratio Test..?
(don't irrelevant Answer and please don't spam the question)​

Answer 1

In mathematics, the ratio test is a test (or "criterion") for the convergence of a series

{\displaystyle \sum _{n=1}^{\infty }a_{n},} \sum _{{n=1}}^{\infty }a_{n},

where each term is a real or complex number and an is nonzero when n is large. The test was first published by Jean le Rond d'Alembert and is sometimes known as d'Alembert's ratio test or as the Cauchy ratio test