Wednesday, November 20, 2019

real analysis - Simple proof that this sequence converges [verification]



This is a relatively simple problem. I'm just making sure I have the right idea here. I'd like to prove that the sequence an=1+1n1/3 converges. My proof is:




We conjecture that an converges to 1. Thus, we must show that, for all ϵR, there exists an N(ϵ)N such that |an1|<ϵ for all n>N(ϵ).



From that inequality, I do some algebra and find that:   n>1ϵ3, so, if we choose N(ϵ)>1ϵ3, we've shown that the sequence converges to 1.



Is this correct?


Answer



Just so this won't go unanswered:
Yes, you're correct. If n>1/ϵ3 then n1/3<ϵ, for all ϵ>0.


No comments:

Post a Comment

analysis - Injection, making bijection

I have injection f:AB and I want to get bijection. Can I just resting codomain to f(A)? I know that every function i...