 # Question: Is A Straight Line A Function?

## What do you call a straight line?

chord – a straight line connecting two points on a curve..

## Is every line a function?

No, every straight line is not a graph of a function. Nearly all linear equations are functions because they pass the vertical line test. The exceptions are relations that fail the vertical line test.

## What is there no horizontal line test for functions?

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. If any horizontal line intersects the graph more than once, the function fails the horizontal line test and is not injective.

## How do you know if a line is horizontal?

This relationship always holds: a slope of zero means that the line is horizontal, and a horizontal line means you’ll get a slope of zero. (By the way, all horizontal lines are of the form “y = some number”, and the equation “y = some number” always graphs as a horizontal line.)

## Is a straight line a function or relation?

A function is a relation with the property that each input is related to exactly one output. A relation is a set of ordered pairs. The graph of a linear function is a straight line, but a vertical line is not the graph of a function.

## What function makes a straight line?

y = m x + b. This is called the equation of a straight line because if we plot the points that satisfy this equation on a graph of y versus x then, as we will see below, the points all lie on a straight line. A typical use of a linear function is to convert from one set of units to another.

## What does a straight line mean in an equation?

i.e., x = y, where (x, y) is any point on the line. … The equation of a straight line is the common relation between the x-coordinate and y-coordinate of any point on the line. Note: The coordinates of any point on the straight line satisfy the equation of the line. Let the equation of a straight line y = 5x – 2.

## Is a straight line a one to one function?

The horizontal line test checks if a function is one-to-one. If a horizontal line passes through a graph more than once, the function has more than one x value for at least one y value, so it cannot be one-to-one.