F(x) = tan(x)= sin(x)/cos(x) lim tan (x) =sin (Pi/2) / cos (Pi/2)= 1/0 = infinite x to Pi/2 so lim tan (x) =1/0 - = - infinite (neg) and lim tan (x) =1/0 + = + infinite (pos) x to (Pi/2)- x to (Pi/2)+ and when x approaches 0, it is very simple lim tan (x) =sin (0) / cos (0)= 0/1 = 0, because sin (0)=0 and cos (0)=1 x to 0