Question

plz make it quick. I've got xam tmro.

Answer 1

if A,B and C are angle of ∆ then from angle sum prop

A+B+C = 180

B. = 180- ( C+A)

B/2 =180/2-(C+A)/2

B/2 =90-(C+A)/2

CotB/2 =cot{90-(C+A)/2}

CotB/2 =tan(C+A)2