Linear Algebra Examples

$[\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}]$

Step 1

Set up the formula to find the characteristic equation $p (λ)$ .

$p (λ) = determinant (A - λ I_{4})$

Step 2

The identity matrix or unit matrix of size $4$ is the $4 \times 4$ square matrix with ones on the main diagonal and zeros elsewhere.

$[\begin{array}{c} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \end{array}]$

Step 3

Substitute the known values into $p (λ) = determinant (A - λ I_{4})$ .

Tap for more steps...

Step 3.1

Substitute $[\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}]$ for $A$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] - λ I_{4})$

Step 3.2

Substitute $[\begin{array}{c} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \end{array}]$ for $I_{4}$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] - λ [\begin{array}{c} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \end{array}])$

Step 4

Simplify.

Tap for more steps...

Step 4.1

Simplify each term.

Tap for more steps...

Step 4.1.1

Multiply $- λ$ by each element of the matrix.

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ \cdot 1 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2

Simplify each element in the matrix.

Tap for more steps...

Step 4.1.2.1

Multiply $- 1$ by $1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.2

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.2.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 λ & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.2.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.3

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.3.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 λ & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.3.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.4

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.4.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 λ \\ - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.4.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.5

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.5.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 λ & - λ \cdot 1 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.5.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ \cdot 1 & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.6

Multiply $- 1$ by $1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & - λ \cdot 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.7

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.7.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 λ & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.7.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.8

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.8.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 λ \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.8.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.9

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.9.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 λ & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.9.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & - λ \cdot 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.10

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.10.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 λ & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.10.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 & - λ \cdot 1 & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.11

Multiply $- 1$ by $1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 & - λ & - λ \cdot 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.12

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.12.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 & - λ & 0 λ \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.12.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 & - λ & 0 \\ - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.13

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.13.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 & - λ & 0 \\ 0 λ & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.13.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 & - λ & 0 \\ 0 & - λ \cdot 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.14

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.14.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 & - λ & 0 \\ 0 & 0 λ & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.14.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 & - λ & 0 \\ 0 & 0 & - λ \cdot 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.15

Multiply $- λ \cdot 0$ .

Tap for more steps...

Step 4.1.2.15.1

Multiply $0$ by $- 1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 & - λ & 0 \\ 0 & 0 & 0 λ & - λ \cdot 1 \end{array}])$

Step 4.1.2.15.2

Multiply $0$ by $λ$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 & - λ & 0 \\ 0 & 0 & 0 & - λ \cdot 1 \end{array}])$

Step 4.1.2.16

Multiply $- 1$ by $1$ .

$p (λ) = determinant ([\begin{array}{c} 1 & 3 & 2 & 11 \\ 0 & - 1 & 3 & 8 \\ 0 & 0 & - 2 & 4 \\ 0 & 0 & 0 & 2 \end{array}] + [\begin{array}{c} - λ & 0 & 0 & 0 \\ 0 & - λ & 0 & 0 \\ 0 & 0 & - λ & 0 \\ 0 & 0 & 0 & - λ \end{array}])$

Step 4.2

Add the corresponding elements.

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 + 0 & 2 + 0 & 11 + 0 \\ 0 + 0 & - 1 - λ & 3 + 0 & 8 + 0 \\ 0 + 0 & 0 + 0 & - 2 - λ & 4 + 0 \\ 0 + 0 & 0 + 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3

Simplify each element.

Tap for more steps...

Step 4.3.1

Add $3$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 + 0 & 11 + 0 \\ 0 + 0 & - 1 - λ & 3 + 0 & 8 + 0 \\ 0 + 0 & 0 + 0 & - 2 - λ & 4 + 0 \\ 0 + 0 & 0 + 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3.2

Add $2$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 & 11 + 0 \\ 0 + 0 & - 1 - λ & 3 + 0 & 8 + 0 \\ 0 + 0 & 0 + 0 & - 2 - λ & 4 + 0 \\ 0 + 0 & 0 + 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3.3

Add $11$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 & 11 \\ 0 + 0 & - 1 - λ & 3 + 0 & 8 + 0 \\ 0 + 0 & 0 + 0 & - 2 - λ & 4 + 0 \\ 0 + 0 & 0 + 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3.4

Add $0$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 & 11 \\ 0 & - 1 - λ & 3 + 0 & 8 + 0 \\ 0 + 0 & 0 + 0 & - 2 - λ & 4 + 0 \\ 0 + 0 & 0 + 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3.5

Add $3$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 & 11 \\ 0 & - 1 - λ & 3 & 8 + 0 \\ 0 + 0 & 0 + 0 & - 2 - λ & 4 + 0 \\ 0 + 0 & 0 + 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3.6

Add $8$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 & 11 \\ 0 & - 1 - λ & 3 & 8 \\ 0 + 0 & 0 + 0 & - 2 - λ & 4 + 0 \\ 0 + 0 & 0 + 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3.7

Add $0$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 & 11 \\ 0 & - 1 - λ & 3 & 8 \\ 0 & 0 + 0 & - 2 - λ & 4 + 0 \\ 0 + 0 & 0 + 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3.8

Add $0$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 & 11 \\ 0 & - 1 - λ & 3 & 8 \\ 0 & 0 & - 2 - λ & 4 + 0 \\ 0 + 0 & 0 + 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3.9

Add $4$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 & 11 \\ 0 & - 1 - λ & 3 & 8 \\ 0 & 0 & - 2 - λ & 4 \\ 0 + 0 & 0 + 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3.10

Add $0$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 & 11 \\ 0 & - 1 - λ & 3 & 8 \\ 0 & 0 & - 2 - λ & 4 \\ 0 & 0 + 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3.11

Add $0$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 & 11 \\ 0 & - 1 - λ & 3 & 8 \\ 0 & 0 & - 2 - λ & 4 \\ 0 & 0 & 0 + 0 & 2 - λ \end{array}]$

Step 4.3.12

Add $0$ and $0$ .

$p (λ) = determinant [\begin{array}{c} 1 - λ & 3 & 2 & 11 \\ 0 & - 1 - λ & 3 & 8 \\ 0 & 0 & - 2 - λ & 4 \\ 0 & 0 & 0 & 2 - λ \end{array}]$

Step 5

Find the determinant.

Tap for more steps...

Step 5.1

Choose the row or column with the most $0$ elements. If there are no $0$ elements choose any row or column. Multiply every element in column $1$ by its cofactor and add.

Tap for more steps...

Step 5.1.1

Consider the corresponding sign chart.

$| \begin{array}{c} + & - & + & - \\ - & + & - & + \\ + & - & + & - \\ - & + & - & + \end{array} |$

Step 5.1.2

The cofactor is the minor with the sign changed if the indices match a $-$ position on the sign chart.

Step 5.1.3

The minor for $a_{11}$ is the determinant with row $1$ and column $1$ deleted.

$| \begin{array}{c} - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \\ 0 & 0 & 2 - λ \end{array} |$

Step 5.1.4

Multiply element $a_{11}$ by its cofactor.

$(1 - λ) | \begin{array}{c} - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \\ 0 & 0 & 2 - λ \end{array} |$

Step 5.1.5

The minor for $a_{21}$ is the determinant with row $2$ and column $1$ deleted.

$| \begin{array}{c} 3 & 2 & 11 \\ 0 & - 2 - λ & 4 \\ 0 & 0 & 2 - λ \end{array} |$

Step 5.1.6

Multiply element $a_{21}$ by its cofactor.

$0 | \begin{array}{c} 3 & 2 & 11 \\ 0 & - 2 - λ & 4 \\ 0 & 0 & 2 - λ \end{array} |$

Step 5.1.7

The minor for $a_{31}$ is the determinant with row $3$ and column $1$ deleted.

$| \begin{array}{c} 3 & 2 & 11 \\ - 1 - λ & 3 & 8 \\ 0 & 0 & 2 - λ \end{array} |$

Step 5.1.8

Multiply element $a_{31}$ by its cofactor.

$0 | \begin{array}{c} 3 & 2 & 11 \\ - 1 - λ & 3 & 8 \\ 0 & 0 & 2 - λ \end{array} |$

Step 5.1.9

The minor for $a_{41}$ is the determinant with row $4$ and column $1$ deleted.

$| \begin{array}{c} 3 & 2 & 11 \\ - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \end{array} |$

Step 5.1.10

Multiply element $a_{41}$ by its cofactor.

$0 | \begin{array}{c} 3 & 2 & 11 \\ - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \end{array} |$

Step 5.1.11

Add the terms together.

$p (λ) = (1 - λ) | \begin{array}{c} - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \\ 0 & 0 & 2 - λ \end{array} | + 0 | \begin{array}{c} 3 & 2 & 11 \\ 0 & - 2 - λ & 4 \\ 0 & 0 & 2 - λ \end{array} | + 0 | \begin{array}{c} 3 & 2 & 11 \\ - 1 - λ & 3 & 8 \\ 0 & 0 & 2 - λ \end{array} | + 0 | \begin{array}{c} 3 & 2 & 11 \\ - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \end{array} |$

Step 5.2

Multiply $0$ by $| \begin{array}{c} 3 & 2 & 11 \\ 0 & - 2 - λ & 4 \\ 0 & 0 & 2 - λ \end{array} |$ .

$p (λ) = (1 - λ) | \begin{array}{c} - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \\ 0 & 0 & 2 - λ \end{array} | + 0 + 0 | \begin{array}{c} 3 & 2 & 11 \\ - 1 - λ & 3 & 8 \\ 0 & 0 & 2 - λ \end{array} | + 0 | \begin{array}{c} 3 & 2 & 11 \\ - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \end{array} |$

Step 5.3

Multiply $0$ by $| \begin{array}{c} 3 & 2 & 11 \\ - 1 - λ & 3 & 8 \\ 0 & 0 & 2 - λ \end{array} |$ .

$p (λ) = (1 - λ) | \begin{array}{c} - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \\ 0 & 0 & 2 - λ \end{array} | + 0 + 0 + 0 | \begin{array}{c} 3 & 2 & 11 \\ - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \end{array} |$

Step 5.4

Multiply $0$ by $| \begin{array}{c} 3 & 2 & 11 \\ - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \end{array} |$ .

$p (λ) = (1 - λ) | \begin{array}{c} - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \\ 0 & 0 & 2 - λ \end{array} | + 0 + 0 + 0$

Step 5.5

Evaluate $| \begin{array}{c} - 1 - λ & 3 & 8 \\ 0 & - 2 - λ & 4 \\ 0 & 0 & 2 - λ \end{array} |$ .

Tap for more steps...

Step 5.5.1

Choose the row or column with the most $0$ elements. If there are no $0$ elements choose any row or column. Multiply every element in column $1$ by its cofactor and add.

Tap for more steps...

Step 5.5.1.1

Consider the corresponding sign chart.

$| \begin{array}{c} + & - & + \\ - & + & - \\ + & - & + \end{array} |$

Step 5.5.1.2

The cofactor is the minor with the sign changed if the indices match a $-$ position on the sign chart.

Step 5.5.1.3

The minor for $a_{11}$ is the determinant with row $1$ and column $1$ deleted.

$| \begin{array}{c} - 2 - λ & 4 \\ 0 & 2 - λ \end{array} |$

Step 5.5.1.4

Multiply element $a_{11}$ by its cofactor.

$(- 1 - λ) | \begin{array}{c} - 2 - λ & 4 \\ 0 & 2 - λ \end{array} |$

Step 5.5.1.5

The minor for $a_{21}$ is the determinant with row $2$ and column $1$ deleted.

$| \begin{array}{c} 3 & 8 \\ 0 & 2 - λ \end{array} |$

Step 5.5.1.6

Multiply element $a_{21}$ by its cofactor.

$0 | \begin{array}{c} 3 & 8 \\ 0 & 2 - λ \end{array} |$

Step 5.5.1.7

The minor for $a_{31}$ is the determinant with row $3$ and column $1$ deleted.

$| \begin{array}{c} 3 & 8 \\ - 2 - λ & 4 \end{array} |$

Step 5.5.1.8

Multiply element $a_{31}$ by its cofactor.

$0 | \begin{array}{c} 3 & 8 \\ - 2 - λ & 4 \end{array} |$

Step 5.5.1.9

Add the terms together.

$p (λ) = (1 - λ) ((- 1 - λ) | \begin{array}{c} - 2 - λ & 4 \\ 0 & 2 - λ \end{array} | + 0 | \begin{array}{c} 3 & 8 \\ 0 & 2 - λ \end{array} | + 0 | \begin{array}{c} 3 & 8 \\ - 2 - λ & 4 \end{array} |) + 0 + 0 + 0$

Step 5.5.2

Multiply $0$ by $| \begin{array}{c} 3 & 8 \\ 0 & 2 - λ \end{array} |$ .

$p (λ) = (1 - λ) ((- 1 - λ) | \begin{array}{c} - 2 - λ & 4 \\ 0 & 2 - λ \end{array} | + 0 + 0 | \begin{array}{c} 3 & 8 \\ - 2 - λ & 4 \end{array} |) + 0 + 0 + 0$

Step 5.5.3

Multiply $0$ by $| \begin{array}{c} 3 & 8 \\ - 2 - λ & 4 \end{array} |$ .

$p (λ) = (1 - λ) ((- 1 - λ) | \begin{array}{c} - 2 - λ & 4 \\ 0 & 2 - λ \end{array} | + 0 + 0) + 0 + 0 + 0$

Step 5.5.4

Evaluate $| \begin{array}{c} - 2 - λ & 4 \\ 0 & 2 - λ \end{array} |$ .

Tap for more steps...

Step 5.5.4.1

The determinant of a $2 \times 2$ matrix can be found using the formula $| \begin{array}{c} a & b \\ c & d \end{array} | = a d - c b$ .

$p (λ) = (1 - λ) ((- 1 - λ) ((- 2 - λ) (2 - λ) + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2

Simplify the determinant.

Tap for more steps...

Step 5.5.4.2.1

Simplify each term.

Tap for more steps...

Step 5.5.4.2.1.1

Expand $(- 2 - λ) (2 - λ)$ using the FOIL Method.

Tap for more steps...

Step 5.5.4.2.1.1.1

Apply the distributive property.

$p (λ) = (1 - λ) ((- 1 - λ) (- 2 (2 - λ) - λ (2 - λ) + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.1.2

Apply the distributive property.

$p (λ) = (1 - λ) ((- 1 - λ) (- 2 \cdot 2 - 2 (- λ) - λ (2 - λ) + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.1.3

Apply the distributive property.

$p (λ) = (1 - λ) ((- 1 - λ) (- 2 \cdot 2 - 2 (- λ) - λ \cdot 2 - λ (- λ) + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.2

Simplify and combine like terms.

Tap for more steps...

Step 5.5.4.2.1.2.1

Simplify each term.

Tap for more steps...

Step 5.5.4.2.1.2.1.1

Multiply $- 2$ by $2$ .

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 - 2 (- λ) - λ \cdot 2 - λ (- λ) + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.2.1.2

Multiply $- 1$ by $- 2$ .

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 + 2 λ - λ \cdot 2 - λ (- λ) + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.2.1.3

Multiply $2$ by $- 1$ .

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 + 2 λ - 2 λ - λ (- λ) + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.2.1.4

Rewrite using the commutative property of multiplication.

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 + 2 λ - 2 λ - 1 \cdot - 1 λ \cdot λ + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.2.1.5

Multiply $λ$ by $λ$ by adding the exponents.

Tap for more steps...

Step 5.5.4.2.1.2.1.5.1

Move $λ$ .

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 + 2 λ - 2 λ - 1 \cdot - 1 (λ \cdot λ) + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.2.1.5.2

Multiply $λ$ by $λ$ .

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 + 2 λ - 2 λ - 1 \cdot - 1 λ^{2} + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.2.1.6

Multiply $- 1$ by $- 1$ .

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 + 2 λ - 2 λ + 1 λ^{2} + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.2.1.7

Multiply $λ^{2}$ by $1$ .

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 + 2 λ - 2 λ + λ^{2} + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.2.2

Subtract $2 λ$ from $2 λ$ .

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 + 0 + λ^{2} + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.2.3

Add $- 4$ and $0$ .

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 + λ^{2} + 0 \cdot 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.1.3

Multiply $0$ by $4$ .

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 + λ^{2} + 0) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.2

Add $- 4 + λ^{2}$ and $0$ .

$p (λ) = (1 - λ) ((- 1 - λ) (- 4 + λ^{2}) + 0 + 0) + 0 + 0 + 0$

Step 5.5.4.2.3

Reorder $- 4$ and $λ^{2}$ .

$p (λ) = (1 - λ) ((- 1 - λ) (λ^{2} - 4) + 0 + 0) + 0 + 0 + 0$

Step 5.5.5

Simplify the determinant.

Tap for more steps...

Step 5.5.5.1

Combine the opposite terms in $(- 1 - λ) (λ^{2} - 4) + 0 + 0$ .

Tap for more steps...

Step 5.5.5.1.1

Add $(- 1 - λ) (λ^{2} - 4)$ and $0$ .

$p (λ) = (1 - λ) ((- 1 - λ) (λ^{2} - 4) + 0) + 0 + 0 + 0$

Step 5.5.5.1.2

Add $(- 1 - λ) (λ^{2} - 4)$ and $0$ .

$p (λ) = (1 - λ) ((- 1 - λ) (λ^{2} - 4)) + 0 + 0 + 0$

Step 5.5.5.2

Expand $(- 1 - λ) (λ^{2} - 4)$ using the FOIL Method.

Tap for more steps...

Step 5.5.5.2.1

Apply the distributive property.

$p (λ) = (1 - λ) (- 1 (λ^{2} - 4) - λ (λ^{2} - 4)) + 0 + 0 + 0$

Step 5.5.5.2.2

Apply the distributive property.

$p (λ) = (1 - λ) (- 1 λ^{2} - 1 \cdot - 4 - λ (λ^{2} - 4)) + 0 + 0 + 0$

Step 5.5.5.2.3

Apply the distributive property.

$p (λ) = (1 - λ) (- 1 λ^{2} - 1 \cdot - 4 - λ \cdot λ^{2} - λ \cdot - 4) + 0 + 0 + 0$

Step 5.5.5.3

Simplify each term.

Tap for more steps...

Step 5.5.5.3.1

Rewrite $- 1 λ^{2}$ as $- λ^{2}$ .

$p (λ) = (1 - λ) (- λ^{2} - 1 \cdot - 4 - λ \cdot λ^{2} - λ \cdot - 4) + 0 + 0 + 0$

Step 5.5.5.3.2

Multiply $- 1$ by $- 4$ .

$p (λ) = (1 - λ) (- λ^{2} + 4 - λ \cdot λ^{2} - λ \cdot - 4) + 0 + 0 + 0$

Step 5.5.5.3.3

Multiply $λ$ by $λ^{2}$ by adding the exponents.

Tap for more steps...

Step 5.5.5.3.3.1

Move $λ^{2}$ .

$p (λ) = (1 - λ) (- λ^{2} + 4 - (λ^{2} λ) - λ \cdot - 4) + 0 + 0 + 0$

Step 5.5.5.3.3.2

Multiply $λ^{2}$ by $λ$ .

Tap for more steps...

Step 5.5.5.3.3.2.1

Raise $λ$ to the power of $1$ .

$p (λ) = (1 - λ) (- λ^{2} + 4 - (λ^{2} λ^{1}) - λ \cdot - 4) + 0 + 0 + 0$

Step 5.5.5.3.3.2.2

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$p (λ) = (1 - λ) (- λ^{2} + 4 - λ^{2 + 1} - λ \cdot - 4) + 0 + 0 + 0$

Step 5.5.5.3.3.3

Add $2$ and $1$ .

$p (λ) = (1 - λ) (- λ^{2} + 4 - λ^{3} - λ \cdot - 4) + 0 + 0 + 0$

Step 5.5.5.3.4

Multiply $- 4$ by $- 1$ .

$p (λ) = (1 - λ) (- λ^{2} + 4 - λ^{3} + 4 λ) + 0 + 0 + 0$

Step 5.5.5.4

Move $4$ .

$p (λ) = (1 - λ) (- λ^{2} - λ^{3} + 4 λ + 4) + 0 + 0 + 0$

Step 5.5.5.5

Reorder $- λ^{2}$ and $- λ^{3}$ .

$p (λ) = (1 - λ) (- λ^{3} - λ^{2} + 4 λ + 4) + 0 + 0 + 0$

Step 5.6

Simplify the determinant.

Tap for more steps...

Step 5.6.1

Combine the opposite terms in $(1 - λ) (- λ^{3} - λ^{2} + 4 λ + 4) + 0 + 0 + 0$ .

Tap for more steps...

Step 5.6.1.1

Add $(1 - λ) (- λ^{3} - λ^{2} + 4 λ + 4)$ and $0$ .

$p (λ) = (1 - λ) (- λ^{3} - λ^{2} + 4 λ + 4) + 0 + 0$

Step 5.6.1.2

Add $(1 - λ) (- λ^{3} - λ^{2} + 4 λ + 4)$ and $0$ .

$p (λ) = (1 - λ) (- λ^{3} - λ^{2} + 4 λ + 4) + 0$

Step 5.6.1.3

Add $(1 - λ) (- λ^{3} - λ^{2} + 4 λ + 4)$ and $0$ .

$p (λ) = (1 - λ) (- λ^{3} - λ^{2} + 4 λ + 4)$

Step 5.6.2

Expand $(1 - λ) (- λ^{3} - λ^{2} + 4 λ + 4)$ by multiplying each term in the first expression by each term in the second expression.

$p (λ) = 1 (- λ^{3}) + 1 (- λ^{2}) + 1 (4 λ) + 1 \cdot 4 - λ (- λ^{3}) - λ (- λ^{2}) - λ (4 λ) - λ \cdot 4$

Step 5.6.3

Combine the opposite terms in $1 (- λ^{3}) + 1 (- λ^{2}) + 1 (4 λ) + 1 \cdot 4 - λ (- λ^{3}) - λ (- λ^{2}) - λ (4 λ) - λ \cdot 4$ .

Tap for more steps...

Step 5.6.3.1

Reorder the factors in the terms $1 (4 λ)$ and $- λ \cdot 4$ .

$p (λ) = 1 (- λ^{3}) + 1 (- λ^{2}) + 1 \cdot 4 λ + 1 \cdot 4 - λ (- λ^{3}) - λ (- λ^{2}) - λ (4 λ) - 1 \cdot 4 λ$

Step 5.6.3.2

Subtract $4 λ$ from $1 \cdot 4 λ$ .

$p (λ) = 1 (- λ^{3}) + 1 (- λ^{2}) + 1 \cdot 4 - λ (- λ^{3}) - λ (- λ^{2}) - λ (4 λ) + 0$

Step 5.6.3.3

Add $1 (- λ^{3}) + 1 (- λ^{2}) + 1 \cdot 4 - λ (- λ^{3}) - λ (- λ^{2}) - λ (4 λ)$ and $0$ .

$p (λ) = 1 (- λ^{3}) + 1 (- λ^{2}) + 1 \cdot 4 - λ (- λ^{3}) - λ (- λ^{2}) - λ (4 λ)$

Step 5.6.4

Simplify each term.

Tap for more steps...

Step 5.6.4.1

Multiply $- λ^{3}$ by $1$ .

$p (λ) = - λ^{3} + 1 (- λ^{2}) + 1 \cdot 4 - λ (- λ^{3}) - λ (- λ^{2}) - λ (4 λ)$

Step 5.6.4.2

Multiply $- λ^{2}$ by $1$ .

$p (λ) = - λ^{3} - λ^{2} + 1 \cdot 4 - λ (- λ^{3}) - λ (- λ^{2}) - λ (4 λ)$

Step 5.6.4.3

Multiply $4$ by $1$ .

$p (λ) = - λ^{3} - λ^{2} + 4 - λ (- λ^{3}) - λ (- λ^{2}) - λ (4 λ)$

Step 5.6.4.4

Rewrite using the commutative property of multiplication.

$p (λ) = - λ^{3} - λ^{2} + 4 - 1 \cdot - 1 λ \cdot λ^{3} - λ (- λ^{2}) - λ (4 λ)$

Step 5.6.4.5

Multiply $λ$ by $λ^{3}$ by adding the exponents.

Tap for more steps...

Step 5.6.4.5.1

Move $λ^{3}$ .

$p (λ) = - λ^{3} - λ^{2} + 4 - 1 \cdot - 1 (λ^{3} λ) - λ (- λ^{2}) - λ (4 λ)$

Step 5.6.4.5.2

Multiply $λ^{3}$ by $λ$ .

Tap for more steps...

Step 5.6.4.5.2.1

Raise $λ$ to the power of $1$ .

$p (λ) = - λ^{3} - λ^{2} + 4 - 1 \cdot - 1 (λ^{3} λ^{1}) - λ (- λ^{2}) - λ (4 λ)$

Step 5.6.4.5.2.2

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$p (λ) = - λ^{3} - λ^{2} + 4 - 1 \cdot - 1 λ^{3 + 1} - λ (- λ^{2}) - λ (4 λ)$

Step 5.6.4.5.3

Add $3$ and $1$ .

$p (λ) = - λ^{3} - λ^{2} + 4 - 1 \cdot - 1 λ^{4} - λ (- λ^{2}) - λ (4 λ)$

Step 5.6.4.6

Multiply $- 1$ by $- 1$ .

$p (λ) = - λ^{3} - λ^{2} + 4 + 1 λ^{4} - λ (- λ^{2}) - λ (4 λ)$

Step 5.6.4.7

Multiply $λ^{4}$ by $1$ .

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} - λ (- λ^{2}) - λ (4 λ)$

Step 5.6.4.8

Rewrite using the commutative property of multiplication.

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} - 1 \cdot - 1 λ \cdot λ^{2} - λ (4 λ)$

Step 5.6.4.9

Multiply $λ$ by $λ^{2}$ by adding the exponents.

Tap for more steps...

Step 5.6.4.9.1

Move $λ^{2}$ .

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} - 1 \cdot - 1 (λ^{2} λ) - λ (4 λ)$

Step 5.6.4.9.2

Multiply $λ^{2}$ by $λ$ .

Tap for more steps...

Step 5.6.4.9.2.1

Raise $λ$ to the power of $1$ .

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} - 1 \cdot - 1 (λ^{2} λ^{1}) - λ (4 λ)$

Step 5.6.4.9.2.2

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} - 1 \cdot - 1 λ^{2 + 1} - λ (4 λ)$

Step 5.6.4.9.3

Add $2$ and $1$ .

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} - 1 \cdot - 1 λ^{3} - λ (4 λ)$

Step 5.6.4.10

Multiply $- 1$ by $- 1$ .

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} + 1 λ^{3} - λ (4 λ)$

Step 5.6.4.11

Multiply $λ^{3}$ by $1$ .

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} + λ^{3} - λ (4 λ)$

Step 5.6.4.12

Rewrite using the commutative property of multiplication.

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} + λ^{3} - 1 \cdot 4 λ \cdot λ$

Step 5.6.4.13

Multiply $λ$ by $λ$ by adding the exponents.

Tap for more steps...

Step 5.6.4.13.1

Move $λ$ .

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} + λ^{3} - 1 \cdot 4 (λ \cdot λ)$

Step 5.6.4.13.2

Multiply $λ$ by $λ$ .

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} + λ^{3} - 1 \cdot 4 λ^{2}$

Step 5.6.4.14

Multiply $- 1$ by $4$ .

$p (λ) = - λ^{3} - λ^{2} + 4 + λ^{4} + λ^{3} - 4 λ^{2}$

Step 5.6.5

Combine the opposite terms in $- λ^{3} - λ^{2} + 4 + λ^{4} + λ^{3} - 4 λ^{2}$ .

Tap for more steps...

Step 5.6.5.1

Add $- λ^{3}$ and $λ^{3}$ .

$p (λ) = - λ^{2} + 4 + λ^{4} + 0 - 4 λ^{2}$

Step 5.6.5.2

Add $- λ^{2} + 4 + λ^{4}$ and $0$ .

$p (λ) = - λ^{2} + 4 + λ^{4} - 4 λ^{2}$

Step 5.6.6

Subtract $4 λ^{2}$ from $- λ^{2}$ .

$p (λ) = - 5 λ^{2} + 4 + λ^{4}$

Step 5.6.7

Move $4$ .

$p (λ) = - 5 λ^{2} + λ^{4} + 4$

Step 5.6.8

Reorder $- 5 λ^{2}$ and $λ^{4}$ .

$p (λ) = λ^{4} - 5 λ^{2} + 4$

Step 6

Set the characteristic polynomial equal to $0$ to find the eigenvalues $λ$ .

$λ^{4} - 5 λ^{2} + 4 = 0$

Step 7

Solve for $λ$ .

Tap for more steps...

Step 7.1

Substitute $u = λ^{2}$ into the equation. This will make the quadratic formula easy to use.

$u^{2} - 5 u + 4 = 0$

$u = λ^{2}$

Step 7.2

Factor $u^{2} - 5 u + 4$ using the AC method.

Tap for more steps...

Step 7.2.1

Consider the form $x^{2} + b x + c$ . Find a pair of integers whose product is $c$ and whose sum is $b$ . In this case, whose product is $4$ and whose sum is $- 5$ .

$- 4, - 1$

Step 7.2.2

Write the factored form using these integers.

$(u - 4) (u - 1) = 0$

Step 7.3

If any individual factor on the left side of the equation is equal to $0$ , the entire expression will be equal to $0$ .

$u - 4 = 0$

$u - 1 = 0$

Step 7.4

Set $u - 4$ equal to $0$ and solve for $u$ .

Tap for more steps...

Step 7.4.1

Set $u - 4$ equal to $0$ .

$u - 4 = 0$

Step 7.4.2

Add $4$ to both sides of the equation.

$u = 4$

Step 7.5

Set $u - 1$ equal to $0$ and solve for $u$ .

Tap for more steps...

Step 7.5.1

Set $u - 1$ equal to $0$ .

$u - 1 = 0$

Step 7.5.2

Add $1$ to both sides of the equation.

$u = 1$

Step 7.6

The final solution is all the values that make $(u - 4) (u - 1) = 0$ true.

$u = 4, 1$

Step 7.7

Substitute the real value of $u = λ^{2}$ back into the solved equation.

$λ^{2} = 4$

${(λ^{2})}^{1} = 1$

Step 7.8

Solve the first equation for $λ$ .

$λ^{2} = 4$

Step 7.9

Solve the equation for $λ$ .

Tap for more steps...

Step 7.9.1

Take the specified root of both sides of the equation to eliminate the exponent on the left side.

$λ = \pm \sqrt{4}$

Step 7.9.2

Simplify $\pm \sqrt{4}$ .

Tap for more steps...

Step 7.9.2.1

Rewrite $4$ as $2^{2}$ .

$λ = \pm \sqrt{2^{2}}$

Step 7.9.2.2

Pull terms out from under the radical, assuming positive real numbers.

$λ = \pm 2$

Step 7.9.3

The complete solution is the result of both the positive and negative portions of the solution.

Tap for more steps...

Step 7.9.3.1

First, use the positive value of the $\pm$ to find the first solution.

$λ = 2$

Step 7.9.3.2

Next, use the negative value of the $\pm$ to find the second solution.

$λ = - 2$

Step 7.9.3.3

The complete solution is the result of both the positive and negative portions of the solution.

$λ = 2, - 2$

Step 7.10

Solve the second equation for $λ$ .

${(λ^{2})}^{1} = 1$

Step 7.11

Solve the equation for $λ$ .

Tap for more steps...

Step 7.11.1

Remove parentheses.

$λ^{2} = 1$

Step 7.11.2

Take the specified root of both sides of the equation to eliminate the exponent on the left side.

$λ = \pm \sqrt{1}$

Step 7.11.3

Any root of $1$ is $1$ .

$λ = \pm 1$

Step 7.11.4

The complete solution is the result of both the positive and negative portions of the solution.

Tap for more steps...

Step 7.11.4.1

First, use the positive value of the $\pm$ to find the first solution.

$λ = 1$

Step 7.11.4.2

Next, use the negative value of the $\pm$ to find the second solution.

$λ = - 1$

Step 7.11.4.3

The complete solution is the result of both the positive and negative portions of the solution.

$λ = 1, - 1$

Step 7.12

The solution to $λ^{4} - 5 λ^{2} + 4 = 0$ is $λ = 2, - 2, 1, - 1$ .

$λ = 2, - 2, 1, - 1$