The mathematical operations we have discussed so far are exact
. Given precise input, their results are exact formulas.
In many situations, however, you do not need an exact result. It may be quite sufficient, for example, to find an approximate
formula that is valid, say, when the quantity x
Power series are approximate formulas that play much the same role with respect to algebraic expressions as approximate numbers play with respect to numerical expressions. Mathematica
allows you to perform operations on power series, in all cases maintaining the appropriate order or "degree of precision" for the resulting power series.