Integration of Function of Two Variables

In summary, the conversation is about a student who needs help with integrating a function of two variables for their physics class. They haven't learned how to do it yet in their calculus classes and are looking for someone to explain it to them. The function is \int (z 2 + x2)-3/2 dx and the answer is x/ sqrt (z2 + x2) z2. After some suggestions and hints, the student realizes that they can use trig substitution to solve the problem.
  • #1
PeterFer
6
0

Homework Statement




For one of my physics classes I need to integrate a function of two variables, but I haven't learned how to do it yet in my calculus classes. If anyone could explain to me how to do it, it would be much appreciated. It's probably pretty simple I just haven't learned it yet.

the integral is [tex]\int[/tex] (z 2 + x2)-3/2 dx



and i know that the answer is x/ sqrt (z2 + x2) z2


thanks
 
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  • #2
PeterFer said:

Homework Statement




For one of my physics classes I need to integrate a function of two variables, but I haven't learned how to do it yet in my calculus classes. If anyone could explain to me how to do it, it would be much appreciated. It's probably pretty simple I just haven't learned it yet.

the integral is [tex]\int[/tex] (z 2 + x2)-3/2 dx

and i know that the answer is x/ sqrt (z2 + x2) z2


thanks

z^2 is a constant with respect to x. That might help.
 
  • #3
yea I've been trying to think of it that way but everything i do doesn't end up working and I can't think of anything else to do
 
  • #4
You can make a trig substitution.
 
  • #5
I think I understand where the sqrt(z2 + x2) in the denominator of the answer comes from, if you pretend z2 + x2 is one term and take its anti-derivative you get 1/sqrt(z2 + x2), but i don't know where the x in the numerator or the z2 in the denominator come from
 
  • #6
What happens if you make x= ztan[tex] \theta[/tex].
 
  • #7
╔(σ_σ)╝ said:
What happens if you make x= ztan[tex] \theta[/tex].

oh wow thank you so much, I completely forgot about trig substitution. Thanks a lot I just got it
 

1. What is the concept of integration of function of two variables?

The integration of function of two variables is a mathematical process that involves finding the area under a surface or a curve in a two-dimensional coordinate system. It is an extension of the single-variable integration, where the function is integrated with respect to one variable. In this case, the function is integrated with respect to two variables, usually denoted as x and y, and the result is a numerical value.

2. What are the methods of integrating a function of two variables?

There are two main methods of integrating a function of two variables: double integration and iterated integration. In double integration, the function is integrated with respect to one variable first, and then the resulting expression is integrated with respect to the other variable. In iterated integration, the function is integrated with respect to one variable while holding the other variable constant, and then the resulting expression is integrated with respect to the other variable while holding the first variable constant.

3. What are the applications of integration of function of two variables?

The integration of function of two variables has various applications in mathematics, physics, and engineering. It is used to find the volume under a curved surface, calculate the mass and center of mass of an object, and solve optimization problems. It is also used in fields such as economics, biology, and statistics to model and analyze complex systems.

4. How is integration of function of two variables related to differentiation?

The integration of function of two variables is the inverse process of differentiation. Just as differentiation is used to find the slope of a function at a point, integration is used to find the area under a curve or a surface. The Fundamental Theorem of Calculus states that differentiation and integration are inverse operations, meaning that integrating a function and then differentiating the result will give back the original function.

5. Can every function of two variables be integrated?

No, not every function of two variables can be integrated. Some functions may have complex or undefined areas, making it impossible to find a definite integral. Some functions may also have no closed form expression for their integrals, requiring numerical methods for approximation. However, for continuous functions, a definite integral can always be found using appropriate techniques.

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