Algebra Examples
[4231]
Step 1
Step 1.1
Set up the formula to find the characteristic equation p(λ).
p(λ)=determinant(A-λI2)
Step 1.2
The identity matrix or unit matrix of size 2 is the 2×2 square matrix with ones on the main diagonal and zeros elsewhere.
[1001]
Step 1.3
Substitute the known values into p(λ)=determinant(A-λI2).
Step 1.3.1
Substitute [4231] for A.
p(λ)=determinant([4231]-λI2)
Step 1.3.2
Substitute [1001] for I2.
p(λ)=determinant([4231]-λ[1001])
p(λ)=determinant([4231]-λ[1001])
Step 1.4
Simplify.
Step 1.4.1
Simplify each term.
Step 1.4.1.1
Multiply -λ by each element of the matrix.
p(λ)=determinant([4231]+[-λ⋅1-λ⋅0-λ⋅0-λ⋅1])
Step 1.4.1.2
Simplify each element in the matrix.
Step 1.4.1.2.1
Multiply -1 by 1.
p(λ)=determinant([4231]+[-λ-λ⋅0-λ⋅0-λ⋅1])
Step 1.4.1.2.2
Multiply -λ⋅0.
Step 1.4.1.2.2.1
Multiply 0 by -1.
p(λ)=determinant([4231]+[-λ0λ-λ⋅0-λ⋅1])
Step 1.4.1.2.2.2
Multiply 0 by λ.
p(λ)=determinant([4231]+[-λ0-λ⋅0-λ⋅1])
p(λ)=determinant([4231]+[-λ0-λ⋅0-λ⋅1])
Step 1.4.1.2.3
Multiply -λ⋅0.
Step 1.4.1.2.3.1
Multiply 0 by -1.
p(λ)=determinant([4231]+[-λ00λ-λ⋅1])
Step 1.4.1.2.3.2
Multiply 0 by λ.
p(λ)=determinant([4231]+[-λ00-λ⋅1])
p(λ)=determinant([4231]+[-λ00-λ⋅1])
Step 1.4.1.2.4
Multiply -1 by 1.
p(λ)=determinant([4231]+[-λ00-λ])
p(λ)=determinant([4231]+[-λ00-λ])
p(λ)=determinant([4231]+[-λ00-λ])
Step 1.4.2
Add the corresponding elements.
p(λ)=determinant[4-λ2+03+01-λ]
Step 1.4.3
Simplify each element.
Step 1.4.3.1
Add 2 and 0.
p(λ)=determinant[4-λ23+01-λ]
Step 1.4.3.2
Add 3 and 0.
p(λ)=determinant[4-λ231-λ]
p(λ)=determinant[4-λ231-λ]
p(λ)=determinant[4-λ231-λ]
Step 1.5
Find the determinant.
Step 1.5.1
The determinant of a 2×2 matrix can be found using the formula |abcd|=ad-cb.
p(λ)=(4-λ)(1-λ)-3⋅2
Step 1.5.2
Simplify the determinant.
Step 1.5.2.1
Simplify each term.
Step 1.5.2.1.1
Expand (4-λ)(1-λ) using the FOIL Method.
Step 1.5.2.1.1.1
Apply the distributive property.
p(λ)=4(1-λ)-λ(1-λ)-3⋅2
Step 1.5.2.1.1.2
Apply the distributive property.
p(λ)=4⋅1+4(-λ)-λ(1-λ)-3⋅2
Step 1.5.2.1.1.3
Apply the distributive property.
p(λ)=4⋅1+4(-λ)-λ⋅1-λ(-λ)-3⋅2
p(λ)=4⋅1+4(-λ)-λ⋅1-λ(-λ)-3⋅2
Step 1.5.2.1.2
Simplify and combine like terms.
Step 1.5.2.1.2.1
Simplify each term.
Step 1.5.2.1.2.1.1
Multiply 4 by 1.
p(λ)=4+4(-λ)-λ⋅1-λ(-λ)-3⋅2
Step 1.5.2.1.2.1.2
Multiply -1 by 4.
p(λ)=4-4λ-λ⋅1-λ(-λ)-3⋅2
Step 1.5.2.1.2.1.3
Multiply -1 by 1.
p(λ)=4-4λ-λ-λ(-λ)-3⋅2
Step 1.5.2.1.2.1.4
Rewrite using the commutative property of multiplication.
p(λ)=4-4λ-λ-1⋅-1λ⋅λ-3⋅2
Step 1.5.2.1.2.1.5
Multiply λ by λ by adding the exponents.
Step 1.5.2.1.2.1.5.1
Move λ.
p(λ)=4-4λ-λ-1⋅-1(λ⋅λ)-3⋅2
Step 1.5.2.1.2.1.5.2
Multiply λ by λ.
p(λ)=4-4λ-λ-1⋅-1λ2-3⋅2
p(λ)=4-4λ-λ-1⋅-1λ2-3⋅2
Step 1.5.2.1.2.1.6
Multiply -1 by -1.
p(λ)=4-4λ-λ+1λ2-3⋅2
Step 1.5.2.1.2.1.7
Multiply λ2 by 1.
p(λ)=4-4λ-λ+λ2-3⋅2
p(λ)=4-4λ-λ+λ2-3⋅2
Step 1.5.2.1.2.2
Subtract λ from -4λ.
p(λ)=4-5λ+λ2-3⋅2
p(λ)=4-5λ+λ2-3⋅2
Step 1.5.2.1.3
Multiply -3 by 2.
p(λ)=4-5λ+λ2-6
p(λ)=4-5λ+λ2-6
Step 1.5.2.2
Subtract 6 from 4.
p(λ)=-5λ+λ2-2
Step 1.5.2.3
Reorder -5λ and λ2.
p(λ)=λ2-5λ-2
p(λ)=λ2-5λ-2
p(λ)=λ2-5λ-2
Step 1.6
Set the characteristic polynomial equal to 0 to find the eigenvalues λ.
λ2-5λ-2=0
Step 1.7
Solve for λ.
Step 1.7.1
Use the quadratic formula to find the solutions.
-b±√b2-4(ac)2a
Step 1.7.2
Substitute the values a=1, b=-5, and c=-2 into the quadratic formula and solve for λ.
5±√(-5)2-4⋅(1⋅-2)2⋅1
Step 1.7.3
Simplify.
Step 1.7.3.1
Simplify the numerator.
Step 1.7.3.1.1
Raise -5 to the power of 2.
λ=5±√25-4⋅1⋅-22⋅1
Step 1.7.3.1.2
Multiply -4⋅1⋅-2.
Step 1.7.3.1.2.1
Multiply -4 by 1.
λ=5±√25-4⋅-22⋅1
Step 1.7.3.1.2.2
Multiply -4 by -2.
λ=5±√25+82⋅1
λ=5±√25+82⋅1
Step 1.7.3.1.3
Add 25 and 8.
λ=5±√332⋅1
λ=5±√332⋅1
Step 1.7.3.2
Multiply 2 by 1.
λ=5±√332
λ=5±√332
Step 1.7.4
The final answer is the combination of both solutions.
λ=5+√332,5-√332
λ=5+√332,5-√332
λ=5+√332,5-√332
Step 2
The eigenvector is equal to the null space of the matrix minus the eigenvalue times the identity matrix where N is the null space and I is the identity matrix.
εA=N(A-λI2)
Step 3
Step 3.1
Substitute the known values into the formula.
N([4231]-5+√332[1001])
Step 3.2
Simplify.
Step 3.2.1
Simplify each term.
Step 3.2.1.1
Multiply -5+√332 by each element of the matrix.
[4231]+[-5+√332⋅1-5+√332⋅0-5+√332⋅0-5+√332⋅1]
Step 3.2.1.2
Simplify each element in the matrix.
Step 3.2.1.2.1
Multiply -1 by 1.
[4231]+[-5+√332-5+√332⋅0-5+√332⋅0-5+√332⋅1]
Step 3.2.1.2.2
Multiply -5+√332⋅0.
Step 3.2.1.2.2.1
Multiply 0 by -1.
[4231]+[-5+√33205+√332-5+√332⋅0-5+√332⋅1]
Step 3.2.1.2.2.2
Multiply 0 by 5+√332.
[4231]+[-5+√3320-5+√332⋅0-5+√332⋅1]
[4231]+[-5+√3320-5+√332⋅0-5+√332⋅1]
Step 3.2.1.2.3
Multiply -5+√332⋅0.
Step 3.2.1.2.3.1
Multiply 0 by -1.
[4231]+[-5+√332005+√332-5+√332⋅1]
Step 3.2.1.2.3.2
Multiply 0 by 5+√332.
[4231]+[-5+√33200-5+√332⋅1]
[4231]+[-5+√33200-5+√332⋅1]
Step 3.2.1.2.4
Multiply -1 by 1.
[4231]+[-5+√33200-5+√332]
[4231]+[-5+√33200-5+√332]
[4231]+[-5+√33200-5+√332]
Step 3.2.2
Add the corresponding elements.
[4-5+√3322+03+01-5+√332]
Step 3.2.3
Simplify each element.
Step 3.2.3.1
To write 4 as a fraction with a common denominator, multiply by 22.
[4⋅22-5+√3322+03+01-5+√332]
Step 3.2.3.2
Combine 4 and 22.
[4⋅22-5+√3322+03+01-5+√332]
Step 3.2.3.3
Combine the numerators over the common denominator.
[4⋅2-(5+√33)22+03+01-5+√332]
Step 3.2.3.4
Simplify the numerator.
Step 3.2.3.4.1
Multiply 4 by 2.
[8-(5+√33)22+03+01-5+√332]
Step 3.2.3.4.2
Apply the distributive property.
[8-1⋅5-√3322+03+01-5+√332]
Step 3.2.3.4.3
Multiply -1 by 5.
[8-5-√3322+03+01-5+√332]
Step 3.2.3.4.4
Subtract 5 from 8.
[3-√3322+03+01-5+√332]
[3-√3322+03+01-5+√332]
Step 3.2.3.5
Add 2 and 0.
[3-√33223+01-5+√332]
Step 3.2.3.6
Add 3 and 0.
[3-√332231-5+√332]
Step 3.2.3.7
Write 1 as a fraction with a common denominator.
[3-√3322322-5+√332]
Step 3.2.3.8
Combine the numerators over the common denominator.
[3-√332232-(5+√33)2]
Step 3.2.3.9
Simplify the numerator.
Step 3.2.3.9.1
Apply the distributive property.
[3-√332232-1⋅5-√332]
Step 3.2.3.9.2
Multiply -1 by 5.
[3-√332232-5-√332]
Step 3.2.3.9.3
Subtract 5 from 2.
[3-√33223-3-√332]
[3-√33223-3-√332]
Step 3.2.3.10
Rewrite -3 as -1(3).
[3-√33223-1(3)-√332]
Step 3.2.3.11
Factor -1 out of -√33.
[3-√33223-1(3)-(√33)2]
Step 3.2.3.12
Factor -1 out of -1(3)-(√33).
[3-√33223-1(3+√33)2]
Step 3.2.3.13
Move the negative in front of the fraction.
[3-√33223-3+√332]
[3-√33223-3+√332]
[3-√33223-3+√332]
Step 3.3
Find the null space when λ=5+√332.
Step 3.3.1
Write as an augmented matrix for Ax=0.
[3-√332203-3+√3320]
Step 3.3.2
Find the reduced row echelon form.
Step 3.3.2.1
Multiply each element of R1 by 23-√33 to make the entry at 1,1 a 1.
Step 3.3.2.1.1
Multiply each element of R1 by 23-√33 to make the entry at 1,1 a 1.
[23-√33⋅3-√33223-√33⋅223-√33⋅03-3+√3320]
Step 3.3.2.1.2
Simplify R1.
[1-3+√33603-3+√3320]
[1-3+√33603-3+√3320]
Step 3.3.2.2
Perform the row operation R2=R2-3R1 to make the entry at 2,1 a 0.
Step 3.3.2.2.1
Perform the row operation R2=R2-3R1 to make the entry at 2,1 a 0.
[1-3+√33603-3⋅1-3+√332-3(-3+√336)0-3⋅0]
Step 3.3.2.2.2
Simplify R2.
[1-3+√3360000]
[1-3+√3360000]
[1-3+√3360000]
Step 3.3.3
Use the result matrix to declare the final solution to the system of equations.
x-3+√336y=0
0=0
Step 3.3.4
Write a solution vector by solving in terms of the free variables in each row.
[xy]=[y2+y√336y]
Step 3.3.5
Write the solution as a linear combination of vectors.
[xy]=y[12+√3361]
Step 3.3.6
Write as a solution set.
{y[12+√3361]|y∈R}
Step 3.3.7
The solution is the set of vectors created from the free variables of the system.
{[12+√3361]}
{[12+√3361]}
{[12+√3361]}
Step 4
Step 4.1
Substitute the known values into the formula.
N([4231]-5-√332[1001])
Step 4.2
Simplify.
Step 4.2.1
Simplify each term.
Step 4.2.1.1
Multiply -5-√332 by each element of the matrix.
[4231]+[-5-√332⋅1-5-√332⋅0-5-√332⋅0-5-√332⋅1]
Step 4.2.1.2
Simplify each element in the matrix.
Step 4.2.1.2.1
Multiply -1 by 1.
[4231]+[-5-√332-5-√332⋅0-5-√332⋅0-5-√332⋅1]
Step 4.2.1.2.2
Multiply -5-√332⋅0.
Step 4.2.1.2.2.1
Multiply 0 by -1.
[4231]+[-5-√33205-√332-5-√332⋅0-5-√332⋅1]
Step 4.2.1.2.2.2
Multiply 0 by 5-√332.
[4231]+[-5-√3320-5-√332⋅0-5-√332⋅1]
[4231]+[-5-√3320-5-√332⋅0-5-√332⋅1]
Step 4.2.1.2.3
Multiply -5-√332⋅0.
Step 4.2.1.2.3.1
Multiply 0 by -1.
[4231]+[-5-√332005-√332-5-√332⋅1]
Step 4.2.1.2.3.2
Multiply 0 by 5-√332.
[4231]+[-5-√33200-5-√332⋅1]
[4231]+[-5-√33200-5-√332⋅1]
Step 4.2.1.2.4
Multiply -1 by 1.
[4231]+[-5-√33200-5-√332]
[4231]+[-5-√33200-5-√332]
[4231]+[-5-√33200-5-√332]
Step 4.2.2
Add the corresponding elements.
[4-5-√3322+03+01-5-√332]
Step 4.2.3
Simplify each element.
Step 4.2.3.1
To write 4 as a fraction with a common denominator, multiply by 22.
[4⋅22-5-√3322+03+01-5-√332]
Step 4.2.3.2
Combine 4 and 22.
[4⋅22-5-√3322+03+01-5-√332]
Step 4.2.3.3
Combine the numerators over the common denominator.
[4⋅2-(5-√33)22+03+01-5-√332]
Step 4.2.3.4
Simplify the numerator.
Step 4.2.3.4.1
Multiply 4 by 2.
[8-(5-√33)22+03+01-5-√332]
Step 4.2.3.4.2
Apply the distributive property.
[8-1⋅5--√3322+03+01-5-√332]
Step 4.2.3.4.3
Multiply -1 by 5.
[8-5--√3322+03+01-5-√332]
Step 4.2.3.4.4
Multiply --√33.
Step 4.2.3.4.4.1
Multiply -1 by -1.
[8-5+1√3322+03+01-5-√332]
Step 4.2.3.4.4.2
Multiply √33 by 1.
[8-5+√3322+03+01-5-√332]
[8-5+√3322+03+01-5-√332]
Step 4.2.3.4.5
Subtract 5 from 8.
[3+√3322+03+01-5-√332]
[3+√3322+03+01-5-√332]
Step 4.2.3.5
Add 2 and 0.
[3+√33223+01-5-√332]
Step 4.2.3.6
Add 3 and 0.
[3+√332231-5-√332]
Step 4.2.3.7
Write 1 as a fraction with a common denominator.
[3+√3322322-5-√332]
Step 4.2.3.8
Combine the numerators over the common denominator.
[3+√332232-(5-√33)2]
Step 4.2.3.9
Simplify the numerator.
Step 4.2.3.9.1
Apply the distributive property.
[3+√332232-1⋅5--√332]
Step 4.2.3.9.2
Multiply -1 by 5.
[3+√332232-5--√332]
Step 4.2.3.9.3
Multiply --√33.
Step 4.2.3.9.3.1
Multiply -1 by -1.
[3+√332232-5+1√332]
Step 4.2.3.9.3.2
Multiply √33 by 1.
[3+√332232-5+√332]
[3+√332232-5+√332]
Step 4.2.3.9.4
Subtract 5 from 2.
[3+√33223-3+√332]
[3+√33223-3+√332]
Step 4.2.3.10
Rewrite -3 as -1(3).
[3+√33223-1(3)+√332]
Step 4.2.3.11
Factor -1 out of √33.
[3+√33223-1(3)-1(-√33)2]
Step 4.2.3.12
Factor -1 out of -1(3)-1(-√33).
[3+√33223-1(3-√33)2]
Step 4.2.3.13
Move the negative in front of the fraction.
[3+√33223-3-√332]
[3+√33223-3-√332]
[3+√33223-3-√332]
Step 4.3
Find the null space when λ=5-√332.
Step 4.3.1
Write as an augmented matrix for Ax=0.
[3+√332203-3-√3320]
Step 4.3.2
Find the reduced row echelon form.
Step 4.3.2.1
Multiply each element of R1 by 23+√33 to make the entry at 1,1 a 1.
Step 4.3.2.1.1
Multiply each element of R1 by 23+√33 to make the entry at 1,1 a 1.
[23+√33⋅3+√33223+√33⋅223+√33⋅03-3-√3320]
Step 4.3.2.1.2
Simplify R1.
[1-3-√33603-3-√3320]
[1-3-√33603-3-√3320]
Step 4.3.2.2
Perform the row operation R2=R2-3R1 to make the entry at 2,1 a 0.
Step 4.3.2.2.1
Perform the row operation R2=R2-3R1 to make the entry at 2,1 a 0.
[1-3-√33603-3⋅1-3-√332-3(-3-√336)0-3⋅0]
Step 4.3.2.2.2
Simplify R2.
[1-3-√3360000]
[1-3-√3360000]
[1-3-√3360000]
Step 4.3.3
Use the result matrix to declare the final solution to the system of equations.
x-3-√336y=0
0=0
Step 4.3.4
Write a solution vector by solving in terms of the free variables in each row.
[xy]=[y2-y√336y]
Step 4.3.5
Write the solution as a linear combination of vectors.
[xy]=y[12-√3361]
Step 4.3.6
Write as a solution set.
{y[12-√3361]|y∈R}
Step 4.3.7
The solution is the set of vectors created from the free variables of the system.
{[12-√3361]}
{[12-√3361]}
{[12-√3361]}
Step 5
The eigenspace of A is the list of the vector space for each eigenvalue.
{[12+√3361],[12-√3361]}