Question

(1+tanA)(1+tanB)=2then what is(A+B)

Answer 1

Given (1+tanA)(1+tanB)=2

or 1+tan A+tan B+tan A tan B=2

or tan A+tan B+tan A tan B=1

or tan A+tan B=1-tan A tan B

or (tan A+tan B)/1-tan A tan B=1

or tan(A+B)=1 therefore (A+B) is 45