Log of 2x2 Matrix: Solving e^A= Ʃ (A^k)/k!

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Homework Statement



log of 2x2 matrix [4 3]
[3 4]

Homework Equations



e^X= A X= log A

The Attempt at a Solution



e^A= Ʃ (A^k)/k!

then what to do?
 
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jhendren said:

Homework Statement



log of 2x2 matrix [4 3]
[3 4]

Homework Equations



e^X= A X= log A

The Attempt at a Solution



e^A= Ʃ (A^k)/k!

then what to do?

I'm not sure that what you've done will be much help. Have you learned matrix diagonalization yet? If so, your matrix is diagonalizable. See http://en.wikipedia.org/wiki/Logarithm_of_a_matrix, especially the section titled "Calculating the logarithm of a diagonalizable matrix".
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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