In Delta ABC, if 2(bc cos A + ca cos B + ab c | vedclass

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(C) Using the cosine rule,we have $\cos A = \frac{b^2 + c^2 - a^2}{2bc}$,$\cos B = \frac{a^2 + c^2 - b^2}{2ac}$,and $\cos C = \frac{a^2 + b^2 - c^2}{2

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$a^2 + b^2 + c^2$

Vedclass · Answer

(C) Using the cosine rule,we have $\cos A = \frac{b^2 + c^2 - a^2}{2bc}$,$\cos B = \frac{a^2 + c^2 - b^2}{2ac}$,and $\cos C = \frac{a^2 + b^2 - c^2}{2ab}$.Substituting these into the expression $2(bc \cos A + ca \cos B + ab \cos C)$:$= 2 \left( bc \cdot \frac{b^2 + c^2 - a^2}{2bc} + ca \cdot \frac{a^2 + c^2 - b^2}{2ac} + ab \cdot \frac{a^2 + b^2 - c^2}{2ab} \right)$$= (b^2 + c^2 - a^2) + (a^2 + c^2 - b^2) + (a^2 + b^2 - c^2)$$= a^2 + b^2 + c^2$.

In $\Delta ABC,$ if $2(bc \cos A + ca \cos B + ab \cos C) = $

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