WBJEE 2025 Math Paper

A real skew-symmetric matrix A must satisfy AT=−A. Hence
All diagonal entries aii obey aii=−aii, so aii=0.
For each off-diagonal pair i There are ‌

n(n−1)

2

such independent pairs, so the total number of skew-symmetric n‌times‌n matrices with entries in {−1,0,1} is 3‌

n(n−1)

2