Linear Transformation - The Matrix of (not so hard)

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The discussion revolves around finding a 4x4 matrix representation of a linear transformation T defined by T(B) = [2 3; 4 0] * B, where B is a 2x2 matrix. The basis for M(2x2) is provided, and the user calculates the transformation for each basis element, resulting in a proposed matrix. Other participants confirm that the procedure is correct, emphasizing the importance of verifying the arithmetic and ensuring the image vectors are correctly placed as columns in the matrix. Overall, the user feels reassured about their approach and the correctness of their final answer.
rad0786
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Homework Statement



I have a linear map T:M(2x2) -------> M(2x2) defined by T(B) = [2 3; 4 0] * B

Find a 4 × 4 matrix representation of this linear transformation with respect to the basis of M(2×2)

Homework Equations



T(B) = [2 3; 4 0] * B


and the basis for M(2X2) is:

[1 0; 0 0]
[0 1; 0 0]
[0 0; 1 0]
[0 0; 0 1]



The Attempt at a Solution




T[1 0; 0 0] = [2 3; 4 0]*[1 0; 0 0] = [2 4; 0 0]
T[0 1; 0 0] = [2 3; 4 0]*[0 1; 0 0] = [0 0; 2 4]
T[0 0; 1 0] = [2 3; 4 0]*[0 0; 1 0] = [3 0; 0 0]
T[0 0; 0 1] = [2 3; 4 0]*[0 0; 0 1] = [0 3; 0 0]

Therefore, the matrix would be:

[2 0 3 0;
4 0 0 3;
0 2 0 0;
0 4 0 0]

Could somebody please veryify this for me.

I'd appreciate that
 
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As long as you put the image vectors as columns in the 4x4 matrix, and you multiplied the 2x2 matrices correctly (double check this), you should not be worrying so much.
 
Last edited:
Tom1992 said:
As long as you put the image vectors as columns in the 4x4 matrix, and you multiplied the 2x2 matrices correctly (double this), you should not be worrying so much.

Oh...

So what you are saying is that I DID my procedure correctly...and that final answer would be correct as long as my aritmatic is correct? :smile:

That makes me feel better...
 
rad0786 said:
Oh...

So what you are saying is that I DID my procedure correctly...and that final answer would be correct as long as my aritmatic is correct? :smile:

that's right but double check the products wrt to the ordered basis you have chosen.

whoa, that's it. my dad is kicking me out of the computer for making too many posts.
 
Last edited:
Ohh okay...thanks.

And that is funny lol.
 
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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