Solve Linear Algebra Questions: Finding Inverses and Determinants"

Multiplying both sides of that equation by A^-1, we have (3A+ 6)I= A. Since I is the "identity" matrix, multiplying any matrix by I leaves that matrix unchanged. So (3A+ 6)I= 3A+ 6. Using that in the equation (3A+ 6)I= A, we have 3A+ 6= A which we can solve for A. Having found A, we can find A^-1 (which is what we want) using standard methods for finding the inverse of a matrix.For question 2, we have 4A= A^7. Multiplying both sides of that equation
  • #1
rabihtawil
10
0

Homework Statement



question 1:
If A is a matrix satisfying 3A^2+6A-I=0, find the inverse of A.

question 2:
Let A be a 3x3 matrix with 4A = A^7. Find the possible values det A.

Homework Equations



none

The Attempt at a Solution



this was a very long homework about 17 questions, i solved the others but i got no clue where to start with these, any help is appreciated.

Best Regards.
 
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  • #2
rabihtawil said:
question 1:
If A is a matrix satisfying 3A^2+6A-I=0, find the inverse of A.
HINT: Multiply through by A-1
rabihtawil said:
question 2:
Let A be a 3x3 matrix with 4A = A^7. Find the possible values det A.
HINTs: det(4A) = 4ndet(A) for an nxn matrix. det(A7) = (det(A))7
 
  • #3
Or, for question 1, note that [itex]3A^2+ 6A= I[/itex] so [itex](3A+ 6)A= I[/itex].
 

FAQ: Solve Linear Algebra Questions: Finding Inverses and Determinants"

What is a linear algebra question?

A linear algebra question is a mathematical problem that involves the manipulation and analysis of linear equations, matrices, and vectors.

How do you find the inverse of a matrix?

The inverse of a matrix is found by using a mathematical process known as the Gaussian elimination method. This involves performing row operations on the matrix until it is in reduced row-echelon form, and then using the resulting matrix to construct the inverse.

What is the determinant of a matrix?

The determinant of a matrix is a scalar value that is calculated using the entries of the matrix. It represents the scaling factor by which the matrix transforms the space it operates on. In other words, it is a measure of how the matrix stretches or shrinks space.

Why is finding the inverse and determinant important in linear algebra?

Finding the inverse and determinant of a matrix is important in linear algebra as it allows us to solve systems of linear equations, determine the existence and uniqueness of solutions, and perform various transformations on vectors and matrices. It also has applications in fields such as engineering, physics, and economics.

What are some real-world applications of solving linear algebra questions?

Linear algebra is used in a wide range of applications, including computer graphics, data analysis, cryptography, and optimization. It is also essential in fields such as engineering, physics, and economics for solving problems involving systems of linear equations and transformations.

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