If $a_n$ is decreasing and $\lim_{n \to \infty} a_n = 0$, then the alternating series $\sum (-1)^n a_n$ converges.

If $\lim_{n \to \infty} |\frac{a_{n+1}}{a_n}| = L$, then the series converges if $L < 1$, diverges if $L > 1$, and is inconclusive if $L = 1$.

If $\lim_{n \to \infty} a_n \neq 0$, then the series $\sum a_n$ diverges.

A function whose domain is the set of natural numbers.

The sum of the terms of a sequence.

Terms approach a specific value (the limit).

Terms do not approach a specific value; the sum is infinite.

Sequence with a constant difference between consecutive terms.

Sequence where each term is the previous term multiplied by a constant ratio.

Series where terms are reciprocals of positive integers.

Series of the form $\sum a_n(x-c)^n$ where $a_n$ are constants and $c$ is a constant.

Series where the terms alternate in sign.

Representation of a function as an infinite sum of terms, with each term being a polynomial function of a single variable.

A Taylor series centered at 0.

Direct Comparison: Compares magnitude directly. Limit Comparison: Compares the limit of the ratio of terms. Direct comparison requires establishing an inequality, limit comparison does not.

Taylor: Expansion around any point c. Maclaurin: Expansion around c=0. Maclaurin is a special case of Taylor.

Alternating Series: Applies only to alternating series, uses the next term. Lagrange: Applies to Taylor polynomials, uses the (n+1)th derivative.

Arithmetic: Constant difference between terms. Geometric: Constant ratio between terms. Arithmetic: Linear growth. Geometric: Exponential growth.