Your equation is NOT a function.
If you rearrange it to read : x^2 - y^2 = 1
you should recognize that it is a hyperbola.
Where did you get the idea a relation cannot be an equation?
All relations are equations.
All functions are relations, but only some relations are functions.
The simplest way to determine if a relation is a function is by means of the "vertical line test"
Visualize a vertical line scanning your graph from left to right. If the line cuts your graph in 2 or more points for a given x value, then it is NOT a function.
relation or function?
x^2 = 1 + y^2
This is a function because relations cannot be an equation right?
1 answer