Calculating integrals involving floor function

In summary, the conversation discusses the possibility of calculating the definite integral ∫[cot(x)]dx from x=0 to x=\pi, where [.] represents the floor function or greatest integer function. It is mentioned that this integral is not converging and cannot be evaluated analytically, but a numeric approximation can be obtained. However, there is a way to evaluate the integral using the limit as delta approaches 0, making it similar to the Cauchy integral. It is also noted that the value of the integral is finite for both the floor and ceiling functions, with limits of -pi/2 and pi/2 respectively. The symmetry of the function can be used to simplify the calculation.
  • #1
smatik
14
1
Is it possible to claculate ∫[cot(x)]dx from x=0 to x=[itex]\pi[/itex]where [.] represents floor functon or the greatest integer function??
it seems impossible to me but can we use the properties of definite integrals to somehow evaluate the area?
 
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  • #2
It is possible to convert this to a series (involving arctan), but I have no idea if this series can be evaluated analytically. It is possible to get a numeric approximation, of course.
 
  • #3
smatik said:
Is it possible to claculate ∫[cot(x)]dx from x=0 to x=[itex]\pi[/itex]where [.] represents floor functon or the greatest integer function?
Impossible because this defined integral is not converging.
 
  • #4
Well, we can consider
$$\lim_{\delta \to 0} \int_\delta^{\pi-\delta} [\cot(x)] dx$$
This should be well-defined and finite.
 
  • #5
Yes, if both limits of the integral tend respectively to 0 and pi, with the same gap (delta), this is similar to the Cauchy integral (Principal Value). Then the limit of the value of the integral is finite : -pi/2 in case of the floor function and pi/2 in case of the ceiling function.
 
  • #6
Right, we can use the symmetry of the function. Nice.
 

1. What is the purpose of calculating integrals involving floor function?

The floor function, denoted by the symbol "⌊x⌋", is a mathematical function that rounds a real number down to the nearest integer. Calculating integrals involving floor function helps in solving problems related to discrete values and can be used in various fields such as computer science, engineering, and finance.

2. How do you calculate integrals involving floor function?

To calculate integrals involving floor function, you can use the properties of floor function and convert the integral into a summation of discrete values. This can be done by breaking the integral into smaller intervals and using the definition of floor function to express the integral in terms of a summation.

3. Can integrals involving floor function have infinite solutions?

No, integrals involving floor function have a finite number of solutions. Since the floor function maps real numbers to integers, the integral will only have solutions at specific points where the function changes its value. These points are finite, and therefore, the number of solutions is also finite.

4. Is it possible to approximate integrals involving floor function?

Yes, it is possible to approximate integrals involving floor function. Since the floor function can be expressed as a summation, we can use numerical methods such as the trapezoidal rule or Simpson's rule to approximate the integral. This is useful when the integral cannot be evaluated analytically.

5. What are some real-world applications of calculating integrals involving floor function?

Integrals involving floor function have various real-world applications such as calculating the average number of items sold in a discrete time period, finding the number of iterations in an algorithm, and determining the amount of resources needed for a project with discrete steps. It can also be used in calculating the value of digital options in finance and in analyzing the complexity of algorithms.

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