System of linear equations with complex coefficients

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The discussion focuses on solving systems of linear equations with complex coefficients. It presents two example systems and notes that applying Kramer's Rule fails due to zero determinants. The solution involves forming an augmented matrix and performing row reduction or substituting variables to simplify the equations. It is concluded that the systems have an infinite number of solutions, as variables can be expressed in terms of a free variable. The key takeaway is that these systems can be solved by manipulating the equations rather than relying solely on Kramer's Rule.
Qubix
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1. You have a system of equations of the following form:
x + iy = 0
-ix + z = 0
y - z = 0

or

-2Sqr(5)x - iy = 0
ix - 2Sqr(5)y + 2iz = 0
-2iy - 2Sqr(5)z = 0




2. What is the general way in which I can solve such a system? I've tried Kramer's Rule, but it does not seem to work since Dx, Dy, Dz all give zero.
 
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Qubix said:
1. You have a system of equations of the following form:
x + iy = 0
-ix + z = 0
y - z = 0


Quite easily it can be seen that (0,0,0) is a solution here

What you can do is form an augmented matrix and row reduce.

or take the first equation x+iy=0 and put it such that x= -iy and put that into the other equations that have 'x' in it. You will now have two equations with two unknowns.

Do the same with the other set of equations.
 
. From -ix+ z= 0, ix= z so x= -iz. We also have x= -iy so -iy= -iz or y= z. The last equation is y- z= 0 which says y= z also. That's why all the determinant are 0: this system has an infinite number of solutions. You can choose z to be anything you want and write x and y in terms of z.
 
Thank you very much for your answers :smile:
 
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