A) \[\frac{2\pi }{3}\]
B) \[\frac{\pi }{6}\]
C) \[\frac{5\pi }{3}\]
D) \[\frac{\pi }{3}\]
Correct Answer: D
Solution :
Given,\[l+m+n=0\] ? (i) \[{{l}^{2}}+{{m}^{2}}-{{n}^{2}}=0\] ... (ii) Also\[,\] \[{{l}^{2}}+{{m}^{2}}+{{n}^{2}}=1\] ... (iii) On solving Eqs. (i), (ii) and (iii), we get \[m=\pm \frac{1}{\sqrt{2}},\,\,n=\mp \frac{1}{\sqrt{2}}\]and\[l=0\] \[\therefore \] \[\theta =\frac{\pi }{3}\]or\[\frac{\pi }{2}\]You need to login to perform this action.
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