Direct Comparison Test inequality help

Click For Summary

Homework Help Overview

The discussion revolves around the Direct Comparison Test in the context of inequalities involving logarithmic and polynomial functions, specifically the inequality ln(n) < n^(1/10). Participants are exploring the validity of this inequality for various values of n and its implications for the test.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants have attempted to analyze the inequality by examining graphs of ln(n) versus n^(k). Questions have been raised about the validity of the inequality for different ranges of n, particularly regarding its truth for integer values.

Discussion Status

The discussion is ongoing, with participants providing differing perspectives on the inequality's validity. Some have pointed out specific values of n where the inequality holds, while others are questioning the assumptions behind the inequality's application in the context of the Direct Comparison Test.

Contextual Notes

There is a noted focus on the conditions under which the inequality ln(n) < n^(1/10) is true, with some participants emphasizing the need for justification over an infinitely long interval rather than just specific cases.

dami
Messages
18
Reaction score
0

Homework Statement



Explain why the Direct Comparison Test allows us to use the inequality Ln n < n^(1/10) even though it is not true for a great many n values.

Homework Equations





The Attempt at a Solution


I looked at the graphs of Ln (n) vs. n^(k)
 
Physics news on Phys.org


dami said:

Homework Statement



Explain why the Direct Comparison Test allows us to use the inequality Ln n < n^(1/10) even though it is not true for a great many n values.

Homework Equations





The Attempt at a Solution


I looked at the graphs of Ln (n) vs. n^(k)
And what did you find out?

Also, how did you graph nk?
 


Actually, ln n < n^{1/10} is only true for n < 3 (for integer values of n).
 


dami said:
Actually, ln n < n^{1/10} is only true for n < 3 (for integer values of n).
That is incorrect. The statement ln n < n.1 is true for n = 3, and it is also true for a lot of much larger values.

In this problem you're supposed to provide justification for the assertion that ln n < n.1 for some infinitely long interval.
 


Thanks. Just realized I have been looking at the question the wrong way
 


Just plotted the graph
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K
Replies
29
Views
3K
Replies
8
Views
18K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K