Hay!! Dear user -PROVE THAT COSA + COS(120-A)+COS(120+A)=0❄here is ur answer ❄LHS=> CosA+Cos(120-A) + Cos(120+A)we know that formula( cos C+ cosD = 2cos (C+D)/2.cos (C-D) /2)=> cosA+2cos120 cos-A=> cosA+2cos (180-60) cosA=> cosA+2(-cos60) cosA=> cosA-cosA=> 0Hence PROVED I hope it's HELP you
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