Algebra Examples
[01-16][01−16]
Step 1
Set up the formula to find the characteristic equation p(λ)p(λ).
p(λ)=determinant(A-λI2)p(λ)=determinant(A−λI2)
Step 2
The identity matrix or unit matrix of size 22 is the 2×22×2 square matrix with ones on the main diagonal and zeros elsewhere.
[1001][1001]
Step 3
Step 3.1
Substitute [01-16][01−16] for AA.
p(λ)=determinant([01-16]-λI2)p(λ)=determinant([01−16]−λI2)
Step 3.2
Substitute [1001][1001] for I2I2.
p(λ)=determinant([01-16]-λ[1001])p(λ)=determinant([01−16]−λ[1001])
p(λ)=determinant([01-16]-λ[1001])p(λ)=determinant([01−16]−λ[1001])
Step 4
Step 4.1
Simplify each term.
Step 4.1.1
Multiply -λ−λ by each element of the matrix.
p(λ)=determinant([01-16]+[-λ⋅1-λ⋅0-λ⋅0-λ⋅1])p(λ)=determinant([01−16]+[−λ⋅1−λ⋅0−λ⋅0−λ⋅1])
Step 4.1.2
Simplify each element in the matrix.
Step 4.1.2.1
Multiply -1−1 by 11.
p(λ)=determinant([01-16]+[-λ-λ⋅0-λ⋅0-λ⋅1])p(λ)=determinant([01−16]+[−λ−λ⋅0−λ⋅0−λ⋅1])
Step 4.1.2.2
Multiply -λ⋅0−λ⋅0.
Step 4.1.2.2.1
Multiply 00 by -1−1.
p(λ)=determinant([01-16]+[-λ0λ-λ⋅0-λ⋅1])p(λ)=determinant([01−16]+[−λ0λ−λ⋅0−λ⋅1])
Step 4.1.2.2.2
Multiply 00 by λλ.
p(λ)=determinant([01-16]+[-λ0-λ⋅0-λ⋅1])p(λ)=determinant([01−16]+[−λ0−λ⋅0−λ⋅1])
p(λ)=determinant([01-16]+[-λ0-λ⋅0-λ⋅1])p(λ)=determinant([01−16]+[−λ0−λ⋅0−λ⋅1])
Step 4.1.2.3
Multiply -λ⋅0−λ⋅0.
Step 4.1.2.3.1
Multiply 00 by -1−1.
p(λ)=determinant([01-16]+[-λ00λ-λ⋅1])p(λ)=determinant([01−16]+[−λ00λ−λ⋅1])
Step 4.1.2.3.2
Multiply 00 by λλ.
p(λ)=determinant([01-16]+[-λ00-λ⋅1])p(λ)=determinant([01−16]+[−λ00−λ⋅1])
p(λ)=determinant([01-16]+[-λ00-λ⋅1])p(λ)=determinant([01−16]+[−λ00−λ⋅1])
Step 4.1.2.4
Multiply -1−1 by 11.
p(λ)=determinant([01-16]+[-λ00-λ])p(λ)=determinant([01−16]+[−λ00−λ])
p(λ)=determinant([01-16]+[-λ00-λ])p(λ)=determinant([01−16]+[−λ00−λ])
p(λ)=determinant([01-16]+[-λ00-λ])p(λ)=determinant([01−16]+[−λ00−λ])
Step 4.2
Add the corresponding elements.
p(λ)=determinant[0-λ1+0-1+06-λ]p(λ)=determinant[0−λ1+0−1+06−λ]
Step 4.3
Simplify each element.
Step 4.3.1
Subtract λλ from 00.
p(λ)=determinant[-λ1+0-1+06-λ]p(λ)=determinant[−λ1+0−1+06−λ]
Step 4.3.2
Add 11 and 00.
p(λ)=determinant[-λ1-1+06-λ]p(λ)=determinant[−λ1−1+06−λ]
Step 4.3.3
Add -1−1 and 00.
p(λ)=determinant[-λ1-16-λ]p(λ)=determinant[−λ1−16−λ]
p(λ)=determinant[-λ1-16-λ]p(λ)=determinant[−λ1−16−λ]
p(λ)=determinant[-λ1-16-λ]p(λ)=determinant[−λ1−16−λ]
Step 5
Step 5.1
The determinant of a 2×22×2 matrix can be found using the formula |abcd|=ad-cb∣∣∣abcd∣∣∣=ad−cb.
p(λ)=-λ(6-λ)-(-1⋅1)p(λ)=−λ(6−λ)−(−1⋅1)
Step 5.2
Simplify the determinant.
Step 5.2.1
Simplify each term.
Step 5.2.1.1
Apply the distributive property.
p(λ)=-λ⋅6-λ(-λ)-(-1⋅1)p(λ)=−λ⋅6−λ(−λ)−(−1⋅1)
Step 5.2.1.2
Multiply 66 by -1−1.
p(λ)=-6λ-λ(-λ)-(-1⋅1)p(λ)=−6λ−λ(−λ)−(−1⋅1)
Step 5.2.1.3
Rewrite using the commutative property of multiplication.
p(λ)=-6λ-1⋅-1λ⋅λ-(-1⋅1)p(λ)=−6λ−1⋅−1λ⋅λ−(−1⋅1)
Step 5.2.1.4
Simplify each term.
Step 5.2.1.4.1
Multiply λλ by λλ by adding the exponents.
Step 5.2.1.4.1.1
Move λλ.
p(λ)=-6λ-1⋅-1(λ⋅λ)-(-1⋅1)p(λ)=−6λ−1⋅−1(λ⋅λ)−(−1⋅1)
Step 5.2.1.4.1.2
Multiply λλ by λλ.
p(λ)=-6λ-1⋅-1λ2-(-1⋅1)p(λ)=−6λ−1⋅−1λ2−(−1⋅1)
p(λ)=-6λ-1⋅-1λ2-(-1⋅1)p(λ)=−6λ−1⋅−1λ2−(−1⋅1)
Step 5.2.1.4.2
Multiply -1−1 by -1−1.
p(λ)=-6λ+1λ2-(-1⋅1)p(λ)=−6λ+1λ2−(−1⋅1)
Step 5.2.1.4.3
Multiply λ2λ2 by 11.
p(λ)=-6λ+λ2-(-1⋅1)p(λ)=−6λ+λ2−(−1⋅1)
p(λ)=-6λ+λ2-(-1⋅1)p(λ)=−6λ+λ2−(−1⋅1)
Step 5.2.1.5
Multiply -(-1⋅1)−(−1⋅1).
Step 5.2.1.5.1
Multiply -1−1 by 11.
p(λ)=-6λ+λ2--1p(λ)=−6λ+λ2−−1
Step 5.2.1.5.2
Multiply -1−1 by -1−1.
p(λ)=-6λ+λ2+1p(λ)=−6λ+λ2+1
p(λ)=-6λ+λ2+1p(λ)=−6λ+λ2+1
p(λ)=-6λ+λ2+1p(λ)=−6λ+λ2+1
Step 5.2.2
Reorder -6λ−6λ and λ2λ2.
p(λ)=λ2-6λ+1p(λ)=λ2−6λ+1
p(λ)=λ2-6λ+1p(λ)=λ2−6λ+1
p(λ)=λ2-6λ+1p(λ)=λ2−6λ+1