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The least positive integer n such that (...

The least positive integer n such that `({:(cos""((pi)/(4)),sin""((pi)/(4))),(-sin""((pi)/(4)),cos""((pi)/(4))):})^n` is an identity matrix of order 2 is

A

4

B

8

C

12

D

16

Text Solution

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The correct Answer is:
B
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CHHAYA PUBLICATION-QUESTION PAPER -2018-WBJEE
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  9. Let vecalpha,vecbeta,vecgamma be three unit vectors such that vecalpha...

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  10. The least positive integer n such that ({:(cos""((pi)/(4)),sin""((pi)/...

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  13. Let f(x)={{:(-2sinx" if "xle-(pi)/(2)),(Asinx+B" if "-(pi)/2ltxlt(pi)/...

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  16. Let I=int0^1(x^3cos3x)/(2+x^2)dx. Then

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