What is the difference between a function and a program on the TI-89?

On the TI-89, a function is a mathematical relationship that takes inputs and produces outputs, allowing for calculations and graphing. In contrast, a program is a sequence of instructions written in TI-Basic or another supported language that can perform complex tasks, automate calculations, or manipulate data. While functions are typically used for single calculations, programs can execute multiple functions and handle more elaborate logic and user interactions.