If $k = \sin \frac{\pi }{{18}}\,.\,\sin \frac{{5\pi }}{{18}}\,.\,\sin \frac{{7\pi }}{{18}},$ then the numerical value of $k$ is
If $k = \sin \frac{\pi }{{18}}\,.\,\sin \frac{{5\pi }}{{18}}\,.\,\sin \frac{{7\pi }}{{18}},$ then the numerical value of $k$ is
- [IIT 1993]
- A
$\frac{1}{4}$
- B
$\frac{1}{8}$
- C
$\frac{1}{{16}}$
- D
None of these
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- [IIT 1977]
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