MCQ
$\sum\limits_{\lambda  = 1}^{10} {{{\sin }^{ - 1}}\left( {\sin \left( {\lambda \pi  - \frac{\pi }{6}} \right)} \right)} $ is equal to-
  • A
    $\frac{{5\pi }}{3}$
  • B
    $\frac{{\pi }}{2}$
  • $0$
  • D
    $5\pi$

Answer

Correct option: C.
$0$
c
$ = \sum\limits_{n = 1}^5 {{{\sin }^{ - 1}}\left( {\sin \left( {2n\pi  - \frac{\pi }{6}} \right)} \right) + } \sum\limits_{n = 1}^5 {{{\sin }^{ - 1}}\left( {\sin \left( {2n - 1} \right)\pi  - \frac{\pi }{6}} \right)} $

$ = \sum\limits_{n = 1}^5 {{{\sin }^{ - 1}}\left( { - \sin \frac{\pi }{6}} \right) + \sum\limits_{n = 1}^5 {{{\sin }^{ - 1}}\left( {\sin \frac{\pi }{6}} \right)} } $

$ =  - \frac{{5\pi }}{6} + \frac{{5\pi }}{6} = 0$

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