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If n ge 2 is an integer A= [(cos (2pi/n)...

If `n ge 2` is an integer `A= [(cos (2pi/n), sin (2pi/n),0),(-sin (2pi/n), cos (2pi/n), 0),(0,0,1)]` and I is the identity matrix of order 3. Then 1) `A^n= I` and `A^(n-1)!= 1` 2) `A^m!= I` for any positive integer m 3) Ais not invertible 4) `A^m= 0` for a positive integer m

A

`A^(n) = I and A^(n- 1)ne I`

B

`A^(m) ne I` for any positive integer m

C

A is not invertibe

D

`A^(m)` = 0 for a positive integer m

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The correct Answer is:
A
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MTG-WBJEE-MATRICES AND DETERMINANTS -WB JEE PREVIOUS YEARS QUESTIONS (CATEGORY 1 : SINGLE OPTION CORRECT TYPE )
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