$\epsilon$ definition of a sequence not converging to a certain number

75 Views Asked by At

I've been trying to solve a bunch of problems regarding how a sequence doesn't converge to a certain number, like how $$\lim_{n\to\infty}\frac{n+1}{2n+3}\ne1$$ $$\lim_{n\to\infty}\frac{n}{n+2}\ne1$$ but I don't understand the definition, how is the inequality $|L-a_n|\ge\epsilon$ going to help me find infinity $a_n$ that aren't in $(L-\epsilon, L+\epsilon)$?