Eigenvectors of coupled 2 different mass system

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Homework Statement


Solve the coupled mass spring problem for two different masses. Similar to the Shankar example:
(d/dt)2x1=-2*w1*x1 + w1*x2
(d/dt)2x2=w2*x1 -2*w2*x2

where
w1= k/m1
w2 = k/m2

Homework Equations


Eigenvalue problem: UX=uX
Diagonalization: A=UDUt
Exponential Matrices: eA

The Attempt at a Solution


Starting off is simple enough. Taking the eigenvalue problem and solving for the eigenvalues.
L1 = -(w1+w2)+sqrt[ (w1+w2)2 - 3w1w2]
and L2 is the same as L1 but a minus in front of the sqrt

My problem lies when plugging back in the eigenvalues to solve for the eigenvectors. It seems straightforward but it is not. When plugging eigenvalues back into the matrix, trying to solve for eigenvector solution for both equations within the matrix is a tricky task.
Does anyone here know any required tricks that are needed to solve for the eigenvectors?

Many books stray away from this problem and resort to the system where the two masses are the same.
Any help is really appreciated.
 
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Please disregard this posting. I have figured the solution.
 
To solve this, I first used the units to work out that a= m* a/m, i.e. t=z/λ. This would allow you to determine the time duration within an interval section by section and then add this to the previous ones to obtain the age of the respective layer. However, this would require a constant thickness per year for each interval. However, since this is most likely not the case, my next consideration was that the age must be the integral of a 1/λ(z) function, which I cannot model.
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