The correct option is B 1
Given A+B=45∘ and tanA+tanB=1
Using the formula, (a+b)2=a2+b2+2ab (tanA+tanB)2=(tanA)2+(tanB)2+2tanAtanB
We know, tan(A+B)=(tanA+tanB)/(1−tanAtanB)
Since A+B=45∘⇒tan(A+B)=tan45∘=1
Also tanA+tanB=1
Therefore 1=1/(1−tanAtanB)⇒tanAtanB=0
Therefore (tanA+tanB)2=(tanA)2+(tanB)2+2tanAtanB
(1)2=(tanA)2+(tanB)2+0
⇒(tanA)2+(tanB)2=1