Let A and B be two skew symmetric matrices.
Then,
A=−AT...()
B=−BT…(2)
Adding equation (1) and (2)
A+B=−AT−BT
⇒A+B=−(AT+BT)
⇒A+B=−(A+B)T
[∵(A+B)T=AT+BT]
If AT=−A or A=−AT then A is called skew-symmetric matrix.
∴A+B is also skew symmetric matrix.
Hence, Sum of two skew symmetric matrices is always skew-symmetric matrix.