Proving the Limit of x_n = 1/sqrt(n) as n Approaches Infinity

  • Thread starter Thread starter _Andreas
  • Start date Start date
  • Tags Tags
    Limit
Click For Summary
SUMMARY

The limit of the sequence x_n = 1/sqrt(n) as n approaches infinity is proven to be 0. The discussion clarifies that for any E > 0, there exists a natural number N such that N > 1/E^2, ensuring that 1/sqrt(n) < E for all n > N. The initial confusion regarding the relationship between N and E is resolved by correctly identifying the necessary condition for proving the limit.

PREREQUISITES
  • Understanding of limits in calculus
  • Familiarity with sequences and their convergence
  • Knowledge of inequalities and their manipulation
  • Basic proficiency in mathematical proofs
NEXT STEPS
  • Study the formal definition of limits in calculus
  • Explore convergence criteria for sequences
  • Learn about epsilon-delta proofs in mathematical analysis
  • Investigate the properties of square roots and their implications in limits
USEFUL FOR

Students studying calculus, mathematics educators, and anyone interested in understanding the principles of limits and sequence convergence.

_Andreas
Messages
141
Reaction score
1

Homework Statement



x_n=1/sqrt(n)

Prove that lim x_n = 0 as n approaches infinity

Homework Equations



E > 0

The Attempt at a Solution



There is a natural number N such that N>1/sqrt(E). There is also a number n>N>1/sqrt(E) <==> sqrt(n)>1/sqrt(sqrt(E)) ==> E>sqrt(sqrt(E))>1/sqrt(n). If this last inequality is correct, I can prove the limit in question. But it can't be, because E<sqrt(sqrt(E)) if 0<E<1. So, what should I do instead?
 
Physics news on Phys.org
You've got this all twisted around. You want 1/sqrt(n)<E for n>N. So you want N>1/E^2.
 
Dick said:
You've got this all twisted around. You want 1/sqrt(n)<E for n>N. So you want N>1/E^2.

I see; it's N I'm after. Thank you!
 

Similar threads

  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K