If-in-triangle-ABC-cosB-b-cosC-c-show-that-the-triangle-is-isosceles-

Question Number 46570 by scientist last updated on 28/Oct/18

I f i n t r i a n g l e A B C \frac{c o s B}{b} = \frac{c o s C}{c}, s h o w t h a t t h e

t r i a n g l e i s i s o s c e l e s

Answered by tanmay.chaudhury50@gmail.com last updated on 28/Oct/18

\frac{s i n A}{a} = \frac{s i n B}{b} = \frac{s i n C}{c}

\frac{c o s B}{c o s C} = \frac{s i n B}{s i n C} = \frac{b}{c}

s i n B c o s C - s i n C c o s B = 0

s i n (B - C) = 0 s o B - C = 0

∠ B = ∠ C p r o v e d