Maths-

General

Easy

Question

# A skew symmetric matrix S satisfies the relation S^{2} + I = 0, where I is a unit matrix, then SS´ is -

- I
- 2I
- –I
- –2I

## The correct answer is: I

### Since s is skew symmetric, S´ = – S,

S^{2} = – I

S.S = –I

S.S.S´ = –I(S´) = IS = S

S^{–1} S S S´ = S^{–1}S

SS´ = I

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