lim tan(3*x) x->oo
Limit(tan(3*x), x, oo, dir='-')
<-oo, oo>
lim tan(3*x) x->0+
0
= 2.83423040880181e-26
lim tan(3*x) x->0-
= -2.83423040880181e-26
2.83423040880181e-26