What Makes a Function Special?
Think of a function as a machine that gives you exactly one output for every input you put in. Unlike regular relations that can be messy, functions follow a strict rule: each x-value (input) gets paired with only one y-value (output).
You'll see functions written as f(x), where x is what you put in and f(x) is what comes out. The cool thing is that functions can be shown in five different ways: ordered pairs like {(1,2), (2,3)}, tables, mapping diagrams, graphs, or equations.
Here's a quick test for graphs: use the vertical line test. If you can draw a vertical line that touches the graph more than once, it's not a function!
💡 Quick Tip: Remember "one input, one output" - that's the golden rule of functions!
Real-life functions are super common. Your daily salary works like S(n) = 500n if you earn P500 per day. Even your phone's battery drain follows a function like B(h) = 100 - 12h, where it loses 12% every hour.