Question

in triangle abc write tan a + b divided by 2 in terms of angle C

Answer 1

In a ΔABC 
∠A+∠B+∠C = 180°
       ∠A+∠B =180°-∠C 

So tan A/2+B/2 = tan(180°/2-c/2)
                         = tan(90°-c/2)

(by identity tan(90°-∅) = cot∅)

                         =cot c/2

:) Hope it helps!!!!!!!