For a triangle ABC, the value of cos2A+cos2B+cos2C is least. If its inradius is 3 and incentre is M, then which of the following is NOT correct?

Question

For a triangle

A B C

, the value of

\cos 2 A + \cos 2 B + \cos 2 C

is least. If its inradius is

3

and incentre is

M

, then which of the following is NOT correct?

Perimeter of

∆ A B C

18 \sqrt{3}

\sin 2 A + \sin 2 B + \sin 2 C = \sin A + \sin B + \sin C

\vec{MA} \cdot \vec{MB} = - 18

area of

∆ A B C

\frac{27 \sqrt{3}}{2}

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