Limits are entered using the lim command. The value the limit approaches is placed in brackets. Limits are the main use of the -> code which produces an arrow.
Examples:
is entered as lim(x->3) 3x/4
is entered as lim(h->0) (f(x+h)-f(x))/h
is entered as lim(x->1+) h(x)
is entered as lim(x->inf)(5x2-4x+2)/(3x2+3x-2)