Enter a 3×3 symmetric matrix a that has entries a11=4, a22=1, a33=3, a21=5, a13=2, and a23=0.

 The required matrix A is

Step-by-step explanation:  We are given to write a 3 × 3 symmetric matrix A that has entries as follows :

We know that in a symmetric matrix,

Since A is a 3 × 3 symmetric matrix, so we must have

Therefore, the 3 × 3 symmetric matrix A is written as follows :

Thus, the required matrix A is