Consider a 3 ×3matrix A whose (i,j)-th element, ai,j = (i-j)3 . Then the matrix A will be
Correct Answer :
skew-symmetric.
Solution :
The correct option is skew-symmetric.
To determine the nature of the matrix , let us analyze its elements. The matrix is a matrix where the element in the -th row and -th column is given by the formula:
Recall the definition of a skew-symmetric matrix. A matrix is skew-symmetric if its transpose is equal to its negative, which means:
In terms of individual elements, this condition is written as:
for all indices and .
Let us check if this property holds for the elements of matrix :
We can factor out from the term inside the parenthesis:
Now, substituting this back into the expression for gives:
Since the cube of is (i.e., ), we get:
Using the definition of , we have:
Additionally, let us evaluate the diagonal elements where :
All diagonal elements are zero, which is a key property of a skew-symmetric matrix.
Since the relation holds true for all and , the matrix is skew-symmetric.
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