If Tan−1x+Tan−1y+Tan−1z=π2 then
xy+yz+zx=1
x2+y2+z2+2xyz=1
x+y+z=xyz
None of these
Let tan-1x=A, tan-1y=B and tan-1z=C ⇒tanA=x, tanB=y and tanC=z
Now tan−1x+tan−1y+tan−1z=π2⇒A+B+C=π2
⇒tanAtanB+tanBtanC+tanCtanA=1 ⇒xy+yz+zx=1