A) \[I\]
B) \[2I\]
C) \[-I\]
D) None of these
Correct Answer: A
Solution :
Since, \[M\] is skew-symmetric matrix \[M'=-M\] Also, \[{{M}^{2}}+I=0\] \[\Rightarrow \] \[{{M}^{2}}=-I+0=-I\] \[\Rightarrow \] \[M\cdot M=-I\] \[\Rightarrow \] \[M\,\,M\,\,M'=IM'=I(-M')=IM=M\] \[\Rightarrow \] \[{{M}^{-1}}MMM'={{M}^{-1}}M\] \[\Rightarrow \] \[IMM'=I\] \[\Rightarrow \] \[MM'=I\]You need to login to perform this action.
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