Question

could you find the answer​

Answer 1

Sum of interior angles of a triangle ABC = 180°

A + B + C = 180°

Dividing by 2 on both sides

( A + B + C)/2 = 180°/2

(A + B)/2 + C/2 = 90°

(A + B)/2 = 90° - C/2

Taking tan on both sides

tan (A + B)/2 = tan ( 90° - C/2 )

tan (A + B) /2 = cot C/2

Since tan x = cot ( 90° - x)

Hence proved.