What is the change of variable for proving the fractional part integral?

  • Context: MHB 
  • Thread starter Thread starter alyafey22
  • Start date Start date
  • Tags Tags
    fractional Integral
Click For Summary
SUMMARY

The integral $$\int^1_0 \left \{ \frac{1}{x} \right \} \, dx$$ evaluates to $$1 - \gamma$$, where $$\gamma$$ represents the Euler-Mascheroni constant. By applying the change of variable $$\frac{1}{x} = t$$, the integral transforms into $$\int_{1}^{\infty} \frac{\{t\}}{t^{2}} \, dt$$. This leads to the conclusion that the limit of the expression $$\lim_{n \rightarrow \infty} (\ln n - \sum_{k=2}^{n} \frac{1}{k})$$ results in the value $$1 - \gamma$$.

PREREQUISITES
  • Understanding of integral calculus
  • Familiarity with the concept of fractional parts
  • Knowledge of the Euler-Mascheroni constant ($$\gamma$$)
  • Experience with change of variables in integrals
NEXT STEPS
  • Study the properties of the Euler-Mascheroni constant ($$\gamma$$)
  • Learn about fractional part functions and their applications in integrals
  • Explore advanced techniques in integral calculus, particularly change of variables
  • Investigate the convergence of series and limits in calculus
USEFUL FOR

Mathematicians, students studying calculus, and anyone interested in advanced integral evaluation techniques.

alyafey22
Gold Member
MHB
Messages
1,556
Reaction score
2
Prove the following
$$\int^1_0 \left \{ \frac{1}{x} \right \} \, dx = 1- \gamma $$​
 
Physics news on Phys.org
ZaidAlyafey said:
Prove the following
$$\int^1_0 \left \{ \frac{1}{x} \right \} \, dx = 1- \gamma $$​

[sp]With the change of variable $\displaystyle \frac{1}{x}= t $ the integral becomes...

$\displaystyle \int_{0}^{1} \{\frac{1}{x}\}\ d x = \int_{1}^{\infty} \frac{\{t\}}{t^{2}}\ d t = \sum_{n=2}^{\infty} \int_{n-1}^{n} (\frac{1}{t} - \frac{n-1}{t^{2}})\ d t = \lim_{n \rightarrow \infty} (\ln n - \sum_{k=2}^{n} \frac{1}{k})= 1 - \gamma$[/sp]

Kind regards

$\chi$ $\sigma$
 

Similar threads

  • · Replies 11 ·
Replies
11
Views
1K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 17 ·
Replies
17
Views
5K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K