Ch 2 — Relations and Functions

Cartesian product A × B is the set of ordered pairs. A relation is any subset of A × B. A function assigns exactly one output to each input in the domain.

From pairs to machines

Cartesian product A × B is the set of ordered pairs. A relation is any subset of A × B. A function assigns exactly one output to each input in the domain.

Domain restrictions: denominators ≠ 0, even roots ≥ 0, log arguments > 0.
Know modulus, signum, greatest-integer, and standard real functions from NCERT.
Vertical line test: a graph is a function if no vertical line hits it twice.

Read this alongside the official NCERT chapter: Relations and Functions — https://ncert.nic.in/textbook.php?kemh1=2-16 (full book index: https://ncert.nic.in/textbook.php?kemh1=0-16).