Int{x=0 to infinity}(exp(-x)*Ln(x)*Ln(x)dx)

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In summary, the conversation discusses the difficulty of solving two integrals and the suggestion to use the Euler gamma constant in the first integral and a Gaussian integral in the second. It is mentioned that the first integral can be written as the Gamma''(1) function and that the Euler's Constant can be represented as Gamma'(1). The conversation is then moved to the Calculus and Analysis forum.
  • #1
mathslover
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I have tried many hours on the following integrals and would appreciate any help from you.


1. Int{x=0 to infinity}(exp(-x)*Ln(x)*Ln(x)dx)

2. Int{x=0 to Infinity}(exp(-x*x)*Ln(x)dx)



Any idea guys?
 
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  • #2
Quickly checked it with Mathematica... the indefinite integrals are no fun (they involve hypergeometric functions and error functions) but the definite integrals come out relatively nicely.

I suppose you will want to somehow use
[tex]\int_0^\infty e^{-t} \ln(t) \, \mathrm dt = -\gamma[/tex]
(the Euler gamma). The second one will also involve a Gaussian integral.

Will think a bit more...
 
  • #3
This has nothing to do with "number theory". I am moving it to Calculus and Analysis.
 
  • #4
For the first integral ,

it can be shown to be = Gamma''(1) and

- Euler's Constant = Gamma'(1)

where Gamma(x)=Gamma Integral

I just don't know how to use the above facts.
 

FAQ: Int{x=0 to infinity}(exp(-x)*Ln(x)*Ln(x)dx)

What are two integrals?

Two integrals refer to the mathematical concept of integrating a function over a given interval or region. It involves finding the area under a curve or the volume of a solid using a specific set of mathematical rules and techniques.

What is the difference between definite and indefinite integrals?

A definite integral has specific upper and lower limits of integration, while an indefinite integral does not have these limits and results in a general solution. In other words, a definite integral gives a specific numerical value, while an indefinite integral gives a function.

What is the fundamental theorem of calculus?

The fundamental theorem of calculus states that differentiation and integration are inverse operations. This means that if a function is integrated and then differentiated, the resulting function will be the same as the original function.

How is integration used in real life?

Integration has many real-life applications, such as calculating the area under a curve in physics and engineering, finding the volume of irregular-shaped objects in architecture, and determining the total cost of a production process in economics.

What are some common techniques for solving integrals?

Some common techniques for solving integrals include substitution, integration by parts, trigonometric substitution, and partial fractions. These techniques involve using specific rules and formulas to simplify the integral and find the solution.

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