- A diagonal matrix is a square matrix where all off-diagonal elements are zero. The diagonal elements can be non-zero.
- A symmetric matrix \(A\) satisfies \(A' = A\), meaning it is equal to its transpose.
- A skew symmetric matrix has all diagonal elements equal to zero. - A row matrix has only one row, as the name suggests.
Thus, the statement "A diagonal matrix has all diagonal elements equal to zero" is false because the diagonal elements can be any value.
An amount of ₹ 10,000 is put into three investments at the rate of 10%, 12% and 15% per annum. The combined annual income of all three investments is ₹ 1,310, however, the combined annual income of the first and second investments is ₹ 190 short of the income from the third. Use matrix method and find the investment amount in each at the beginning of the year.
If \[ A = \begin{bmatrix} 1 & 2 & 0 \\ -2 & -1 & -2 \\ 0 & -1 & 1 \end{bmatrix} \] then find \( A^{-1} \). Hence, solve the system of linear equations: \[ x - 2y = 10, \] \[ 2x - y - z = 8, \] \[ -2y + z = 7. \]