Question

A square matrix $A=[a_{ij}{]}_{n\times n}$, if $a_{ij}=0$ for $i>j,$ then that matrix is known as

• A. Upper triangular matrix
• B. Lower triangluar matrix
• C. Unit matrix
• D. Null matrix

Answer 1

The correct option is A Upper triangular matrix

In upper triangular matrix $A=[a_{ij}{]}_{n\times n}$, we have $a_{ij}=0$ for $i>j$
Example: For $n=3$
$A={\left[\begin{array}{ccc}a& b& c\\ 0& d& e\\ 0& 0& f\end{array}\right]}_{3\times 3}$