Before studying infinite series in AP Calculus BC, we must understand sequences at a conceptual level.
A sequence is not just a list of numbers. It is a function whose inputs are positive integers:
a_n = f(n), \quad n = 1,2,3,\dots
Unlike regular functions defined on intervals, sequences are discrete. We evaluate them only at whole-number inputs.
In BC, sequences help us answer one central question:
What happens as n \to \infty ?
Does the sequence:
Understanding this behavior prepares us for infinite series.
If each term increases by 3, the pattern is predictable and linear.