Question

how do I determine if a function is one-to-one?

Answer 1

Basically if each value in the domain maps to a unique value in the range (i.e. if 1 and 2 are in the domain, they both can't map to 5).

Answer 2

actually that would be codomain, not range

Answer 3

okay for example.. f(x) = x^2 +2x -4
how would I know?

Answer 4

if you can draw it, use a "horizontal" line test

Answer 5

You would do the horizontal line test.



The first one is not a one to one function because when you do the horizontal line test it touches more than one point on the graph.

The second one is one to one function because when you do the horizontal line test it touches the graph in only one place.