Q&A

# Matrix solution software

+2
−0 I am trying to invert the matrix in the picture. I had done mistakes 3 times. And I heard someone in Khanacademy were saying "let computer do the hard tasks". I was trying to find better Matrix solution software online, but I am also willing to install software if it solves my problem.

I had found Matrix Calc. You know what when I had put the above matrix there then that webpage was completely unresponsive.. I found another site called SymbolLab. But the site isn't completely better for matrix. Only addition subtraction is helpful. But not inverse. Sometimes I get Illegal input in that site also.

I had found another one also: https://matrix.reshish.com/matrixMethod.php. In this page I just can deal with simple matrix (just talking about 3x3 matrix for now). But I can do simple inverse matrix in notepad I don't need them to solve simple matrix.

I don't think I should show further research about the topic.

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+3
−0

I recommend Sage. It is an open-source general purpose mathematics software based on Python. You can install it from the link above, or for quick computations, you can also just use their free server: https://sagecell.sagemath.org/

You can find many resources on inverting matrices in Sage online, but here is a quick example in a Sage interpreter:

``````sage: M = Matrix([[1, 4], [2, 3]])
sage: M
[1 4]
[2 3]
sage: M.inverse()
[-3/5  4/5]
[ 2/5 -1/5]
``````
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+3
−0

You could use Maxima. Some packages offer a GUI (Xmaxima or Wxmaxima, if I'm not mistaken), but you can use it in the terminal.

Below, an interactive terminal Maxima session in which I define and invert the two-dimensional rotation matrix.

``````(%i3) m: matrix([cos(x), -sin(x)], [sin(x), cos(x)]);
[ cos(x)  - sin(x) ]
(%o3)                        [                  ]
[ sin(x)   cos(x)  ]
(%i4) m^^-1;
[       cos(x)              sin(x)       ]
[  -----------------   ----------------- ]
[     2         2         2         2    ]
[  sin (x) + cos (x)   sin (x) + cos (x) ]
(%o4)             [                                        ]
[        sin(x)             cos(x)       ]
[ - -----------------  ----------------- ]
[      2         2        2         2    ]
[   sin (x) + cos (x)  sin (x) + cos (x) ]
(%i5) trigsimp(%);
[  cos(x)   sin(x) ]
(%o5)                        [                  ]
[ - sin(x)  cos(x) ]
``````

Note that Maxima is somewhat lazy and leaves even the most elementary trigonometric identities such as sin²(x)+cos²(x) unresolved. I used `trigsimp` on the last output expression, `%`, to simplify the output.

In Maxima, you can use the question mark to find help on a function or operator. For example, `? matrix`.

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