Comparison Theorem and Limits of integration

In summary, the Comparison Theorem is a mathematical tool used in calculus to estimate the behavior of a function by comparing it to another function. It can be used to simplify the analysis of complicated functions and to find the limit of integration in cases where the antiderivative cannot be found analytically. It can be applied to all types of functions but is most commonly used for continuous functions. However, there are some limitations to its use, such as only providing an estimate of the limit of integration and requiring the functions to have the same limit at a certain point. The Comparison Theorem can also be used in other areas of mathematics such as physics, engineering, and statistics.
  • #1
Painguy
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Homework Statement



Why is it that when using the comparison theorem my limits of integration must be from a constant value to infinity and not from negative infinity to infinity?

For example ∫ x/(1+x^2) dx from -∞ to ∞
 
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  • #2
Can you be more specific about what comparison theorem you are talking about?

For your example, notice that if ##x \geq 1##, you can easily check that
$$\frac{x}{1+x^2} \geq \frac{1}{2x}$$
What does that tell you?
 

FAQ: Comparison Theorem and Limits of integration

1. What is the Comparison Theorem and how is it used in calculus?

The Comparison Theorem is a mathematical tool used in calculus to estimate the behavior of a function by comparing it to another function. It states that if two functions have the same limit at a certain point, and one function is always greater than the other in a neighborhood of that point, then the two functions have the same limit at that point. This allows us to simplify the analysis of complicated functions by using simpler, known functions.

2. How does the Comparison Theorem help in finding the limit of integration?

The Comparison Theorem can be applied to find the limit of integration in cases where the antiderivative of a function cannot be found analytically. By comparing the function to a known function with a known limit, we can determine the limit of integration for the original function.

3. Can the Comparison Theorem be used for all types of functions?

Yes, the Comparison Theorem can be used for all types of functions, as long as they satisfy the conditions of the theorem. However, it is most commonly used for continuous functions.

4. Are there any limitations to using the Comparison Theorem?

While the Comparison Theorem is a useful tool in calculus, there are some limitations to its use. It can only be used to compare functions that have the same limit at a certain point, and it may not always provide an exact solution. In some cases, it may only give an estimate of the limit of integration.

5. Can the Comparison Theorem be used in other areas of mathematics?

Yes, the Comparison Theorem is a general mathematical principle and can be applied in various fields such as physics, engineering, and statistics. It is commonly used in the study of differential equations, optimization problems, and in proving the convergence of series.

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