/sin(pi*x)\ lim |---------| x->4+\ -1 + x /
Limit(sin(pi*x)/(-1 + x), x, 4)
0
= 1.16199464221433e-30
/sin(pi*x)\ lim |---------| x->4-\ -1 + x /
= -4.59504650608658e-31
1.16199464221433e-30