- #1

Sparky_

- 227

- 5

## Homework Statement

find the eignevalues (a part of a larger problem) for

A= | -4 1 1 |

| 1 5 -1 |

| 0 1 -3 |

## Homework Equations

## The Attempt at a Solution

= | -4-x 1 1 |

| 1 5-x -1 |

| 0 1 -3-x |

(-4-x)[ (5-x)(-3-x) + 1 ] - (1)[ (1)(-3-x) - 0] + (1)[1-0]

(-4-x)[ x^2 -2x -14] + x + 4

(-4)[-x^3 + 2x^2 + 14x] + x + 4

4x^3 - 8x^2 - 56x + x + 4

4x^3 - 8x^2 - 55x + 4

I do not see the roots for the above being -3, -4, and 5.

The book has x1 = -3, x2 = -4, and x3 = 5.

When I run the eigenvalue routine in the software package Maxima, I believe I am getting (-3 -4,5) - output is a little confusing. - anyway I am seeing the same numbers

When I expand (x+3)(x+4)(x-5)

I get 3x^3 - 3x^2 - 60x.

Help?

Thanks

Sparky_