# Converting Power Series to Normal Expressions

 Normal[expr] convert a power series to a normal expression

Converting power series to normal expressions.

Power series in the Wolfram Language are represented in a special internal form, which keeps track of such attributes as their expansion order.

For some purposes, you may want to convert power series to normal expressions. From a mathematical point of view, this corresponds to truncating the power series, and assuming that all higherorder terms are zero.

This generates a power series, with four terms:
 In:= Out= Squaring the power series gives you another power series, with the appropriate number of terms:
 In:= Out= Normal truncates the power series, giving a normal expression:
 In:= Out= You can now apply standard algebraic operations:
 In:= Out= SeriesCoefficient[series,n] give the coefficient of the n order term in a power series

Extracting coefficients of terms in power series.

This gives the coefficient of in the original power series:
 In:= Out= This gives the coefficient for the term in the Taylor expansion of the function about zero:
 In:= Out= 