Lesson 4 of 48
Function as a black box
One input in, one output out, and the same answer every time.
A function is a promise: give me this, and I return that, always. That promise is what lets you stop thinking about the inside. Later a neural network is a function too — a very large one whose rule you never write down by hand.
Do this
Given a function described only by a table of inputs and outputs, state its rule, predict an output you have not been shown, then produce an input that breaks your guess.
The question that unlocks the next lesson
A “function” returns 7 for input 2 on Monday and 9 for input 2 on Tuesday. What is true?
- AIt is a function with two rules
- BIt is not a function — the same input must give the same output
- CIt is a function as long as both answers are correct
- DIt becomes a function once you average the outputs