Calculus Introduction
Functions
Connect an input to an output through a rule.
Before this
No earlier lesson needed. Start here.
The intuition
A function assigns one output to each allowed input. A model is a function whose adjustable parameters determine its predictions.
A concrete example
For f(x) = 2x + 1, input 3 produces output 7. Changing the coefficient 2 changes the rule, rather than just the input.
What to remember
Inputs and parameters play different roles: inputs describe an observation; parameters define the model.
Check your understanding
What is f(0) for f(x) = 2x + 1?
Reveal explanation
1. The constant term remains when x is zero.