Guys ,i justed wanted to ask out something

if the formula given in NCERT is right

Tan(A+B)=Tan A+Tan B/1-Tan A*Tan B

then dont u think

{ Tan(A +B) }(1-Tan A*Tan B)= Tan A+Tan B

should be right too

but if put A & B =45

then

LHS=Not Defined(0)=Not Defined

&

RHS=1+1=2

whats wrong in formula then