In triangle ABC,what is the value of cos A + | vedclass

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(D) We know that in any $	riangle ABC$,$\cos A + \cos B + \cos C = 1 + 4 \sin \left(\frac{A}{2}ight) \sin \left(\frac{B}{2}ight) \sin \left(\frac

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$1 + \frac{r}{R}$

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(D) We know that in any $	riangle ABC$,$\cos A + \cos B + \cos C = 1 + 4 \sin \left(\frac{A}{2}ight) \sin \left(\frac{B}{2}ight) \sin \left(\frac{C}{2}ight)$.Using the identity for the inradius $r = 4R \sin \left(\frac{A}{2}ight) \sin \left(\frac{B}{2}ight) \sin \left(\frac{C}{2}ight)$,we can substitute the product of sines.Thus,$4 \sin \left(\frac{A}{2}ight) \sin \left(\frac{B}{2}ight) \sin \left(\frac{C}{2}ight) = \frac{r}{R}$.Therefore,$\cos A + \cos B + \cos C = 1 + \frac{r}{R}$.

In $\triangle ABC$,what is the value of $\cos A + \cos B + \cos C$?

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