Solve for Alpha(a): 3 Equations with Unknowns in Matrix - Need Help!

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SUMMARY

The discussion revolves around solving a system of three equations involving the variable alpha(a) to demonstrate that it has two non-trivial solutions. The equations are represented in matrix form as AX = 0, where A is the coefficient matrix. The key to finding the values of a that lead to non-invertibility of matrix A lies in determining when the determinant of A equals zero or through row-reduction methods. The participant is encouraged to explore these methods to identify the required values of a.

PREREQUISITES
  • Understanding of linear algebra concepts, specifically matrix equations.
  • Knowledge of determinant calculations for matrices.
  • Familiarity with row-reduction techniques for solving systems of equations.
  • Basic understanding of non-trivial solutions in linear systems.
NEXT STEPS
  • Learn how to calculate the determinant of a 3x3 matrix.
  • Study row-reduction methods for solving linear equations.
  • Explore the concept of matrix invertibility and its implications.
  • Investigate the conditions for non-trivial solutions in homogeneous systems.
USEFUL FOR

Students studying linear algebra, educators teaching matrix theory, and anyone interested in solving systems of equations involving parameters.

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Homework Statement


the following 3 equations are given, show that alpha(a) has two non trival solutions, then solve for the whole thing:


Homework Equations


ax - 3y + ( 1+a) z = 0
2x + y - az = 0
(a+2)x - 2y + az = 0


i think i may be missing something but i can't seem to even get started on this problem,
thanks
 
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Martinuk said:

Homework Statement


the following 3 equations are given, show that alpha(a) has two non trival solutions, then solve for the whole thing:


Homework Equations


ax - 3y + ( 1+a) z = 0
2x + y - az = 0
(a+2)x - 2y + az = 0


i think i may be missing something but i can't seem to even get started on this problem,
thanks
Well, what HAVE you done? You mention "unknowns in a matrix" so presumably you know how to set this up as a matrix equation. With A as the matrix of coefficients, X as the column matrix <x, y, z> and 0 as the column matrix <0, 0, 0>, your equation is AX= 0. The unique solution will be [itex]X= A^{-1}0= 0[/itex] as long as A has an inverse.

So the question is, "for what values of a does this matrix of coefficients not have an inverse?" I don't know what methods of finding an inverse matrix you have learned but you might try row-reducing the matrix and see what values of a prevent you doing that. Or determine what values of a make the determinant of the matrix 0.
 

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