Grade 11Trigonometry
In a triangle ABC prove that cos A / cos C = c-acosB/ a-cCos B
In a triangle ABC prove that cos A / cos C = c-acosB/ a-cCos B
1 Answer
Arun
Dear student
c = bcosA + acosB and a = bcosC + ccosB
Therefore, c - a cosB = b cosA and a - c cosB = b cosC
Therefore, (c - a cosB)/(a - c cosB) = cosA/cosC
Hence proved
Regards
Arun (askIITians forum expert)
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