please-prove-A-B-C-are-angles-of-triangle-cylic-sinA-sinB-cosc-8cos-A-2-cos-B-2-cos-C-2-

Question Number 107624 by mnjuly1970 last updated on 11/Aug/20

p l e a s e p r o v e :

A, B, C a r e a n g l e s o f

t r i a n g l e .

\sum_{c y l i c} \frac{s i n A + s i n B}{c o s c} ⩾ 8 c o s \frac{A}{2} c o s \frac{B}{2} c o s \frac{C}{2}