tan(A+B)=tan 225=tan45=1
tan(A+B)=(tanA+tanB)/(1-tanAtanB)=1;
tanA+tanB=1-anAtanB
tanA+tanB+tanAtanB=1
(1+tanA)(1+tanB)=tanA+tanB+tanAtanB+1=2
tan(A+B)=tan 225=tan45=1
tan(A+B)=(tanA+tanB)/(1-tanAtanB)=1;
tanA+tanB=1-anAtanB
tanA+tanB+tanAtanB=1
(1+tanA)(1+tanB)=tanA+tanB+tanAtanB+1=2