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

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The discussion focuses on using the tabular method to integrate the function xcos(x^2). The user attempts to apply the method by differentiating cos(x^2) and integrating x, resulting in the derivative column containing -2xsin(x^2) and the integral column (x^2)/2. However, some participants argue that the tabular method may not be the best approach for this integral, suggesting that u-substitution with u=x^2 is a simpler and more effective method. The conversation highlights the importance of recognizing when different integration techniques are more suitable. Ultimately, while the tabular method is a valid technique, alternative methods may yield easier solutions for certain integrals.
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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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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}##.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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