User Aritra Das - Mathematica Stack Exchange most recent 30 from mathematica.stackexchange.com 2019-08-25T19:11:31Z https://mathematica.stackexchange.com/feeds/user/36257 http://www.creativecommons.org/licenses/by-sa/3.0/rdf https://mathematica.stackexchange.com/q/151310 1 Why is tensor product not giving me a block matrix? [closed] Aritra Das https://mathematica.stackexchange.com/users/36257 2017-07-12T19:41:33Z 2017-07-13T01:59:40Z <p>I thought tensor product of $a = \begin{bmatrix} x \\y\end{bmatrix}$ and $b = \begin{bmatrix} 1 &amp; 2 \\3 &amp; 4\end{bmatrix}$ would give me $$a\otimes b = \begin{bmatrix} x &amp; 2x\\3x &amp; 4x\\y &amp; 2y \\ 3y &amp; 4y\end{bmatrix}$$ But what mathematica gives me is, </p> <p><a href="https://i.stack.imgur.com/3SJgz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3SJgz.png" alt="result"></a></p> <p>Where am I going wrong? And what do I need to do in order to get the matrix that I want?</p> https://mathematica.stackexchange.com/q/101739 6 Why does Mathematica spit this back out? Aritra Das https://mathematica.stackexchange.com/users/36257 2015-12-10T19:28:43Z 2015-12-14T11:26:15Z <p>I'm struggling with the integral, $$\iint\sqrt{4a^2-x^2-y^2}dxdy$$ taken over the upper half disk of radius a centered at (a, 0).</p> <p>When I type it into <em>Mathematica</em> (10.2), <em>Mathematica</em> spits it back out. Here's my code.</p> <pre><code>Integrate[Sqrt[4a^2-x^2-y^2]Boole[x^2+y^2&lt;2a x], {x, 0, 2a}, {y, 0, a}] </code></pre> <p>The output <em>Mathematica</em> produces is just the fancy version (2 dimensional) of this. This integration is easy, I've even done it by hand. Why can't <em>Mathematica</em> do it?</p> https://mathematica.stackexchange.com/questions/151310/why-is-tensor-product-not-giving-me-a-block-matrix?cid=403716 Comment by Aritra Das on Why is tensor product not giving me a block matrix? Aritra Das https://mathematica.stackexchange.com/users/36257 2017-07-12T19:44:20Z 2017-07-12T19:44:20Z Thanks a lot. Where was I going wrong though? I mean is what I wanted not really the tensor product?