Question

Is `y=3` a function?

Answer 1

Yes. The equation `y=3` represents the function that maps all `x` values to `3`.

Explanation:

The equation `y=3` represents a horizontal line, which will have exactly one intersection point with any vertical line. So it passes the vertical line test for a function too.

graph{y=3+0.0000001x [-10, 10, -5, 5]}