In a , prove that _ r=0 ^ n ^n C_r a^r b^ n-r (rB - (n-r)A) =…

MATHEMATICS · Subjective · CBSE · Mathematics · Binomial Theorem · Binomial Theorem

Problem

In a ΔABC\Delta ABC , prove that ∑r=0nnCrarbn−rcos⁡(rB−(n−r)A)=cn.\sum_{r=0}^{n} {}^n C_r a^r b^{n-r} \cos(rB - (n-r)A) = c^n.

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