Linked from
The 66 pages that link to Taylor series, each with the reason it gives.
Power seriesBroader topic: It is the standard way to obtain a power series from a function.
Infinite seriesBroader topic: It represents functions locally as infinite sums of polynomial terms.
Ratio testBroader topic: Term ratios can determine where a Taylor series converges.
Series expansionBroader topic: It constructs a local expansion from derivative data.