The function asympt computes the asymptotic expansion of f with respect to the variable x (as x approaches infinity).

The third argument n specifies the truncation order of the series expansion.  If no third argument is given, the value of the global variable Order (default Order = 6) is used.

Specifically, asympt is defined in terms of the series function

However, the expression returned will be in sum-of-products form rather than in the series form.