Answer:
See below.
Step-by-step explanation:
We know that
tanA + tan B
tan (A + B) = ---------------------
1 - tanAtanB
Substituting for A + B
tan (A + B) = tan pi/4 = 1.
tanA + tan B
So ------------------ = 1
1 - tanAtanB
Therefore tanA + tan B = 1 - tanAtanB.
