If in a \[\Delta ABC\], \[\cos 3A+\cos 3B+\cos 3C=1\], then one angle must be exactly equal to

If in a \[\Delta ABC\], \[\cos 3A+\cos 3B+\cos 3C=1\], then one angle

1.	If in a \[\Delta ABC\], \[\cos 3A+\cos 3B+\cos 3C=1\], then one angle must be exactly equal to
A.	\[{{90}^{o}}\]
B.	\[{{45}^{o}}\]
C.	\[{{120}^{o}}\]
D.	None of these
Answer» D. None of these

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If in a \[\Delta ABC\], \[\cos 3A+\cos 3B+\cos 3C=1\], then one angle must be exactly equal to

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