Show steps in a calculation using Wolfram Mathematica 11?

Questions
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1

How to make Mathematica show me the steps of any calculation as example steps of a definite integral

Integrate[1/Sqrt[R^2 + (x1 - x2)^2], {x2, 0, l}, {x1, 0, l}]

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2

In Wolfram Mathematica there is no such possibility yet.

1 Alternative use WolframAlpha only work with 1-dimensional integrals.(paid version)

2 Alternative use Maple only work with 1-dimensional integrals.(paid version)

3 https://www.integral-calculator.com only work with 1-dimensional integrals.(free version)

4 Or another Internet integral-calculators (They have limited possibilities).

Regards,MI

3

Here is a related integral for which W|A will correctly interpret input and offer show-steps.

Integrate[1/Sqrt[Pi^2+x^2],{x,0,E}]

Changing x to x2 makes it go sideways though.

I used concrete values instead of R and l so as to avoid the need to argue with Alpha over whether it should take the Assumptions option of Integrate or otherwise infer ranges of viable values for those parameters.