/2*x*sin(x)\ lim |----------| x->oo\1 - cos(x)/
Limit(((2*x)*sin(x))/(1 - cos(x)), x, oo, dir='-')
/2*x*sin(x)\ lim |----------| x->0+\1 - cos(x)/
4
= 4.0
/2*x*sin(x)\ lim |----------| x->0-\1 - cos(x)/
<-oo, oo>
4.0