Nemanjavuk69
Junior Member
- Joined
- Mar 23, 2022
- Messages
- 71
I have the following matrix
120036−1−10
Following the text book linear algebra and its applications 6 global edition by David C. Lay on chapter 5.2 we can calculate the determinant by writing the characteristic equation like this
1−λ2003−λ6−1−1−λ
However, when doing the calculations I always end up with −λ3+4λ2−3λ−6 and that is not true, the actual equation should be −λ3+4λ2−9λ−6
I am row expanding from the first column, so a11,a21,a31
I can therefor calculate the determinant as followed...
(1−λ)⋅∣∣∣∣∣3−λ6−1−λ∣∣∣∣∣−2⋅∣∣∣∣∣06−1−λ∣∣∣∣∣(1−λ)⋅(3−λ)⋅(−λ)+6−2⋅6(1−λ)⋅(−3λ+λ2)+6−3λ+λ2+3λ2−λ3−6−λ3+4λ2−3λ−6
However, as stated before, the result is not right. Instead of −3λ it should be −9λ. Where am I doing something wrong? Any help is gladely appreciated.
120036−1−10
Following the text book linear algebra and its applications 6 global edition by David C. Lay on chapter 5.2 we can calculate the determinant by writing the characteristic equation like this
1−λ2003−λ6−1−1−λ
However, when doing the calculations I always end up with −λ3+4λ2−3λ−6 and that is not true, the actual equation should be −λ3+4λ2−9λ−6
I am row expanding from the first column, so a11,a21,a31
I can therefor calculate the determinant as followed...
(1−λ)⋅∣∣∣∣∣3−λ6−1−λ∣∣∣∣∣−2⋅∣∣∣∣∣06−1−λ∣∣∣∣∣(1−λ)⋅(3−λ)⋅(−λ)+6−2⋅6(1−λ)⋅(−3λ+λ2)+6−3λ+λ2+3λ2−λ3−6−λ3+4λ2−3λ−6
However, as stated before, the result is not right. Instead of −3λ it should be −9λ. Where am I doing something wrong? Any help is gladely appreciated.