Calculating Determinant of $(N+1) \times (N+1)$ Matrix

In summary, the given $(N+1) \times (N+1)$ matrix has the form of a tridiagonal matrix with the main diagonal elements being $2+h^2q(x_i)$ and the off-diagonal elements being $-1$. It is necessary to show that the determinant of this matrix is not equal to 0 in order to prove that it is invertible. This can be shown by expanding the determinant, which will result in a polynomial of degree $N+1$ with coefficients involving $h$, $q(x_i)$, and $x_i$.
  • #1
evinda
Gold Member
MHB
3,836
0
Hello! (Wave)

Suppose that we are given this $(N+1) \times (N+1)$ matrix: $\begin{bmatrix}
-(1+h+\frac{h^2}{2}q(x_0)) & 1 & 0 & 0 & \dots & \dots & 0 \\
-1 & 2+h^2q(x_1) & -1 & 0 & \dots& \dots & 0\\
0 & -1 & 2+h^2q(x_2) & -1 & 0 & \dots & 0\\
& & & & & & \\
& & & & & & \\
& & & & & & \\
& & & & 0 & -1 & 2+h^2q(x_N)
\end{bmatrix}$ I want to show that the above matrix is invertible.So it suffices to show that the determinant is $\neq 0$, right?

Will the determinant be equal to $-\left( 1+h+\frac{h^2}{2}q(x_0) (2+h^2 q(x_1)) \cdots (2+h^2q(x_N)) +(2+h^2 q(x_2)) \cdots (2+h^2q(x_N)) \right)$?
Or am I wrong? (Thinking)
 
Physics news on Phys.org
  • #2
first line and second column: 1 or –1?
 

FAQ: Calculating Determinant of $(N+1) \times (N+1)$ Matrix

What is the determinant of a matrix?

The determinant of a matrix is a numerical value that can be calculated from the elements of the matrix. It is used to determine certain properties of the matrix, such as whether it is invertible or singular.

How do you calculate the determinant of a (N+1) x (N+1) matrix?

The determinant of a (N+1) x (N+1) matrix can be calculated using various methods, such as cofactor expansion, row or column operations, or using the Leibniz formula. The specific method used will depend on the size and structure of the matrix.

What is the significance of calculating the determinant of a matrix?

Calculating the determinant of a matrix can provide important information about the matrix, such as its invertibility, volume scaling factor, and solutions to systems of linear equations. It is also used in various mathematical and scientific applications, such as in vector calculus and quantum mechanics.

Is there a shortcut or formula for calculating the determinant of a (N+1) x (N+1) matrix?

There is no single shortcut or formula for calculating the determinant of a (N+1) x (N+1) matrix. As mentioned earlier, the method used will depend on the specific characteristics of the matrix. However, there are certain patterns and properties that can be utilized to simplify the calculation process.

Can the determinant of a matrix be negative?

Yes, the determinant of a matrix can be negative. In general, the determinant can be positive, negative, or zero, depending on the elements of the matrix. The sign of the determinant is important in determining the orientation and scaling of vectors and shapes in space.

Similar threads

Back
Top