Chapter 11: Problem 275
Why is the slope of a vertical line undefined?
Short Answer
Expert verified
A vertical line has an undefined slope because division by zero in the slope formula results in an undefined value.
Step by step solution
01
- Identify the Structure of a Vertical Line
A vertical line has the same x-coordinate for all points. For example, a vertical line passing through x = 3 can be represented by the equation x = 3. This means that every point on this line has an x-coordinate of 3, regardless of the y-coordinate.
02
- Apply the Slope Formula to a Vertical Line
When selecting two points on a vertical line, say (3, y_1) and (3, y_2), we observe that the x-coordinates are the same (x_1 = x_2 = 3). Substituting these points into the slope formula, we get: \[ m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{y_2 - y_1}{3 - 3} = \frac{y_2 - y_1}{0} \]. This results in division by zero, which is undefined in mathematics.
03
- Conclusion
Since the denominator in the slope formula for a vertical line is zero, the slope of a vertical line is undefined because division by zero is not possible.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Vertical Line
A vertical line is a unique type of line in geometry. Unlike other lines that can be slanted at various angles, a vertical line runs straight up and down.
What sets a vertical line apart is that it maintains a constant x-coordinate for all its points. For instance, if we consider a vertical line represented by the equation x = 3, then every point on this line has an x-coordinate of 3, regardless of its y-coordinate.
This means any point on the line will look like (3, y), where 'y' can be any value.
What sets a vertical line apart is that it maintains a constant x-coordinate for all its points. For instance, if we consider a vertical line represented by the equation x = 3, then every point on this line has an x-coordinate of 3, regardless of its y-coordinate.
This means any point on the line will look like (3, y), where 'y' can be any value.
Slope Formula
The slope of a line is a measure of its steepness and is calculated using the slope formula.
The slope formula is: \[ m = \frac{y_2 - y_1}{x_2 - x_1} \]
Where:\
The slope formula is: \[ m = \frac{y_2 - y_1}{x_2 - x_1} \]
Where:\
- \( m \) is the slope of the line
- \( (x_1, y_1) \) and \( (x_2, y_2) \) are coordinates of two points on the line
Division by Zero
Division by zero is a key mathematical concept that is not allowed.
In the context of the slope formula, if the x-coordinates of two points are the same (as in the case of a vertical line), the denominator becomes zero.
Let's elaborate: For a vertical line represented by the points \((3, y_1)\) and \(( 3, y_2)\), the slope formula becomes
\[ m = \frac{y_2 - y_1}{3 - 3} = \frac{y_2 - y_1}{0} \]
This results in a division by zero, which is undefined in mathematics because we cannot divide any number by zero.
In the context of the slope formula, if the x-coordinates of two points are the same (as in the case of a vertical line), the denominator becomes zero.
Let's elaborate: For a vertical line represented by the points \((3, y_1)\) and \(( 3, y_2)\), the slope formula becomes
\[ m = \frac{y_2 - y_1}{3 - 3} = \frac{y_2 - y_1}{0} \]
This results in a division by zero, which is undefined in mathematics because we cannot divide any number by zero.
x-coordinate
The x-coordinate is the first part of an ordered pair (x, y) that represents a point on the coordinate plane.
It tells us how far to move horizontally from the origin (0, 0).
In a vertical line, this x-coordinate is the same for all points.
For instance, in the vertical line equation x = 3, the x-coordinate will always be 3.
This uniform x-coordinate is the reason why the denominator in the slope formula for a vertical line is zero, resulting in an undefined slope.
It tells us how far to move horizontally from the origin (0, 0).
In a vertical line, this x-coordinate is the same for all points.
For instance, in the vertical line equation x = 3, the x-coordinate will always be 3.
This uniform x-coordinate is the reason why the denominator in the slope formula for a vertical line is zero, resulting in an undefined slope.
y-coordinate
The y-coordinate is the second part of an ordered pair (x, y) that specifies a point's position on the coordinate plane.
It indicates how far to move vertically from the origin (0, 0).
In the context of a vertical line, the y-coordinate can vary while the x-coordinate remains constant.
This variability ensures that even though the x-coordinate is fixed, multiple points can exist on a vertical line due to different y-coordinates.
It indicates how far to move vertically from the origin (0, 0).
In the context of a vertical line, the y-coordinate can vary while the x-coordinate remains constant.
This variability ensures that even though the x-coordinate is fixed, multiple points can exist on a vertical line due to different y-coordinates.