How can you use the tabular method to integrate xcos(x^2)

In summary, the tabular method is a form of integration by parts, which involves organizing the steps into a table. It is used to solve integrals that can be difficult to solve using other methods. However, in this case, the integral can be easily solved using the u-substitution method.
  • #1
lioric
306
20

Homework Statement


This is not a homework but since asked me I'm posting it here. I know how to intergrate by parts and can do this using formula
But I'd like to do this using the tabular method

Question
Integrate xcos(x^2) using tabular method

Homework Equations


The table with derivative on one volume and integral on the other column

The Attempt at a Solution


I know we can differentiate the one which is harder to intergrate so I integrated the x and differentiated cos(x^2)

So I get -2sin(x^2) for the derivative column and (x^2)/2 on the intergral side
When I multiply the results as said in tabular method and integrate the last portion, I get

(X^2)/2 * cos(x^2) -2 integrated by sin(x^2) * (x^2)/2
 
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  • #2
lioric said:
I know how to intergrate by parts and can do this using formula
But I'd like to do this using the tabular method
The tabular method is integration by parts. It is just organizing the steps into a table. If you understand the formula than there is no need to make a table.
lioric said:
I know we can differentiate the one which is harder to intergrate so I integrated the x and differentiated cos(x^2)

So I get -2sin(x^2) for the derivative column and (x^2)/2 on the intergral side
When I multiply the results as said in tabular method and integrate the last portion, I get

(X^2)/2 * cos(x^2) -2 integrated by sin(x^2) * (x^2)/2
The first derivative is ##-2x\text{sin}(x^{2})## not ##-2\text{sin}(x^{2})##. I don't think this is a good method to solve this problem though. This integral is relatively trivial using the u-substitution ##u=x^{2}##.
 

1. How does the tabular method work for integrating xcos(x^2)?

The tabular method is a technique used to integrate functions that can be expressed as the product of two functions. In this case, we can express xcos(x^2) as (x)(cos(x^2)). The tabular method involves creating a table with the two functions and their derivatives, and using specific rules to find the integral.

2. What are the steps for using the tabular method to integrate xcos(x^2)?

The steps for using the tabular method to integrate xcos(x^2) are:

  1. Create a table with the two functions, x and cos(x^2), and their derivatives, 1 and -2xsin(x^2).
  2. Apply the alternating signs to the derivatives in the second row.
  3. Multiply the corresponding terms in each row and add them together.
  4. Repeat this process until you reach a row with all zeros.
  5. The integral can then be found by adding all the terms in the right column.

3. Can the tabular method be used for any integration problem?

No, the tabular method can only be used for integrating functions that can be expressed as the product of two functions. If the function cannot be expressed in this form, other integration techniques may need to be used.

4. How does the tabular method compare to other integration techniques?

The tabular method is a relatively straightforward and systematic approach to integration, making it a popular choice for solving integration problems. However, it may not always be the most efficient method, and other techniques such as substitution or integration by parts may be more suitable for certain functions.

5. Are there any tips for using the tabular method effectively?

Some tips for using the tabular method effectively include: choosing the correct functions to create the table, being careful with the signs in the second row, and checking your work by differentiating the final result to ensure it matches the original function. Practice and familiarity with the method can also greatly improve its effectiveness.

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