If a,b.c are the angles of a triangle prove that tan a/2 tan b /2+ tan b /2 tan c/2+tan c/2 tan a/2=1
given that a+b+c = 90 where a b c are acute angles prove that
cota +cotb + cotc =cota cotb cotc
更新1:
Why tan a + tan b = 3/2 and tan a tan b = -4 Please teach me how to prove it
