Monday, 10 October 2016

limits - Which function grows faster?



Which function grows faster



𝑓(𝑛)=2𝑛2+3𝑛 and 𝑔(𝑛)=2𝑛+1



by using the limit theorem I will first simplify



then I will just get limn2n2+3n2n+1=limn2n2+3nn1=limn2n2+2n1=




Is this enough?
I say it will go then to infinity so the f(n) is growing faster? I am asking this question because I have to find it by using limit but I didn't need to use l'hopital rule!


Answer



Before Edit:
Your idea was correct, but you didn’t simplify the limit properly.
limn2n2+3n2n+1
It is enough to divide both the numerator and denominator by 2n.
limn2n2+3n2n2n+12n=limn2n2+3nn2nn+12n=limn2n2+2n1+12n
As n, it becomes clear that the limit tends to since the numerator tends to while the denominator tends to 1.




After Edit: Yes, your way is correct.


No comments:

Post a Comment

real analysis - How to find limhrightarrow0fracsin(ha)h

How to find limh0sin(ha)h without lhopital rule? I know when I use lhopital I easy get $$ \lim_{h\rightarrow 0}...