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Triangles : Prove a Trigonometric Relation -- (b +c )cos A+(c +a) cos B+ (a + b)cos C=a+b+c

In any triangle ABC, prove that (b +c )cos A+(c +a) cos B+ (a + b)cos C=a+b+c

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Formula required: Projection Formula

Projection Formula: In any triangle ABC, a=b ...

Solution Summary

A trigonometric relation involving triangles is proven.

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