To find the inverse Laplace transform of a complicated function, we can convert the function to a sum of simpler terms for which we know the Laplace transform of each term. The result is called & partial-fraction expansion. If F1(s) = N1(s)/D1(s), where the order of N(s) is less than the order of D(s), then a partial-fraction expansion can be made. If the order of N(s) is greater than or equal to the order of D(s), then N(s) must be divided by D(s) successively until the result has a remainder whose Numerator is of order less than its denominator.