Question

If tanA = tan B then porve that A+B = 90°?

Answer 1

I think if A and B are the two angles of triangle then,
tan A= tan B 
tan (90-A)= tan B
90 - A = B
90 = A+ B

Answer 2

$let \: tan(90 - a) = tan \: b \\ = 90 - a = b \\ a + b = 90$