In mathematics, the **horizontal line test** is a test used to determine whether a function is injective (i.e., one-to-one).

Read more about Horizontal Line Test: Horizontal Line Test in Calculus, Horizontal Line Test in Set Theory

### Other articles related to "horizontal line test, horizontal lines, horizontal line":

**Horizontal Line Test**in Set Theory

... Consider the

**horizontal lines**in ... The function f is injective if and only if each

**horizontal line**intersects the graph at most once ... In this case the graph is said to pass the

**horizontal line test**...

### Famous quotes containing the words test, horizontal and/or line:

“The *test* of a given phrase would be: Is it worthy to be immortal? To “make a beeline” for something. That’s worthy of being immortal and is immortal in English idiom. “I guess I’ll split” is not going to be immortal and is excludable, therefore excluded.”

—Robert Fitzgerald (1910–1985)

“I am a sort of martyr, as you see,

A *horizontal* monument to patience.

The calves of waitresses parade about

My helpless head upon this sodden floor.

Well, I am down again, but not yet out.

O sweet frustrations, I shall be back for more.”

—Richard Wilbur (b. 1921)

“When I had mapped the pond ... I laid a rule on the map lengthwise, and then breadthwise, and found, to my surprise, that the *line* of greatest length intersected the *line* of greatest breadth exactly at the point of greatest depth.”

—Henry David Thoreau (1817–1862)