Wolfram|Alpha can compute Taylor, Maclaurin, Laurent, Puiseux and other series expansions. A series expansion is a representation of a mathematical expression in terms of one of the variables, often using the derivative of the expression to compute successive terms in the series. A partial sum of a series expansion can be used to approximate a math expression numerically.
Analyze a function using the Taylor power series.
Use a power series with fractional exponents to approximate a function.
Represent a function as a Laurent series.