ACT Preparation / Unit 10 ACT 0901 short lesson, about 20 seconds
What a Function Is
Captions available
The idea
A relation is a set of ordered pairs. A function is a relation that gives each input exactly one output.
In practice
{(1, 4), (2, 4), (3, 7)} is a function; {(1, 4), (1, 5)} is not, since 1 has two outputs.
Where people slip
Two inputs may share an output; one input may not have two outputs.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Something wrong in this lesson? Flag it · Sources for ACT Preparation