Series
Computes a power series expansion.
$ wo 'Series[Exp[x], {x, 0, 4}]'
SeriesData[x, 0, {1, 1, 1/2, 1/6, 1/24}, 0, 5, 1]
Trailing zero coefficients are dropped while the truncation order is kept:
$ wo 'Series[1 + x, {x, 0, 3}]'
SeriesData[x, 0, {1, 1}, 0, 4, 1]
$ wo 'Series[x^2 + x^4, {x, 0, 7}]'
SeriesData[x, 0, {1, 0, 1}, 2, 8, 1]
An expression free of the expansion variable is returned unchanged:
$ wo 'Series[3, {x, 0, 3}]'
3
$ wo 'Series[a + b, {x, 0, 3}]'
a + b
An expansion point of Infinity gives powers of 1/x:
$ wo 'Series[1/(1 + x), {x, Infinity, 3}]'
SeriesData[x, Infinity, {1, -1, 1}, 1, 4, 1]
$ wo 'Normal[Series[Sqrt[x^2 + 1], {x, Infinity, 2}]]'
1/(2*x) + x