Chapter 14: Problem 24
Sketch the graph of the function. $$ f(x, y)=x^{2} $$
Short Answer
Expert verified
The graph is a parabolic cylinder extending infinitely along the \( y \)-axis.
Step by step solution
01
Understanding the Function
The given function is a two-variable function: \( f(x, y) = x^2 \). This function depends on both \( x \) and \( y \), but notice that \( y \) does not appear explicitly in the formula. This means that the function will vary only with changes in \( x \), while \( y \) can take any value.
02
Visualizing the Function
Since the function is \( f(x, y) = x^2 \), every vertical plane parallel to the \( yz \)-plane at some \( x = c \) will look like the parabola \( z = c^2 \). Thus, for each fixed value of \( x \), the output \( z \) is the square of \( x \). However, given that \( y \) is not explicitly part of the function, for every constant \( x \), the graph in the \( yz \)-plane will look exactly the same as along the entire \( x \)-axis.
03
Describing the Graph
The graph of the function \( f(x, y) = x^2 \) can be seen as a surface that resembles a parabolic cylinder. For every fixed value of \( y \), the cross-section of the surface parallels to the \( xz \)-plane forms the parabola \( z = x^2 \). Therefore, this surface extends infinitely in the direction of the \( y \)-axis without any change, representing a parabolic cylinder.
04
Sketching the Graph
To sketch the graph of this function in three dimensions, envision a series of parabolic curves (along the \( xz \)-plane) that are stacked together, forming a continuous surface that runs infinitely parallel along the \( y \)-axis. This creates a parabolic shape which is repeated through all slices parallel to the \( xz \)-plane, resulting in the shape of a parabolic cylinder.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Parabolic Cylinder
In the context of a multivariable function like \( f(x, y) = x^2 \), understanding the shape of a "parabolic cylinder" is essential. This term describes a specific type of surface found in three-dimensional space. A parabolic cylinder is essentially an extrusion of a parabola along a straight line, in this case, the \( y \)-axis.
When you examine the function \( f(x, y) = x^2 \), you realize that it varies based solely on the variable \( x \). Since \( y \) is not present in the equation, it suggests that for any specific plane where \( y \) is constant, the graph will consistently form a parabolic curve. Here, regardless of the value of \( y \), the cross-section is described by \( z = x^2 \).
This continuity along the \( y \)-axis shows why it can be thought of as a cylinder – specifically, a parabolic one, because the cross-sectional shape (the parabola) is repeated infinitely along the axis. This creates a surface that extends infinitely without altering its parabolic nature.
When you examine the function \( f(x, y) = x^2 \), you realize that it varies based solely on the variable \( x \). Since \( y \) is not present in the equation, it suggests that for any specific plane where \( y \) is constant, the graph will consistently form a parabolic curve. Here, regardless of the value of \( y \), the cross-section is described by \( z = x^2 \).
This continuity along the \( y \)-axis shows why it can be thought of as a cylinder – specifically, a parabolic one, because the cross-sectional shape (the parabola) is repeated infinitely along the axis. This creates a surface that extends infinitely without altering its parabolic nature.
3D Graph Sketching
Sketching the graph of a multivariable function like \( f(x, y) = x^2 \) in three dimensions can be a rewarding way to visualize complex surfaces. The goal here is to grasp how the function behaves across the entire space defined by \( x \), \( y \), and \( z \).
To start sketching, recognize that the function only varies with \( x \). This means:
To start sketching, recognize that the function only varies with \( x \). This means:
- For every fixed value of \( x \), the function \( f(x,y) = x^2 \) produces a constant \( z \) value.
- The parabolas formed along each plane parallel to the \( xz \)-plane result in a repeated pattern along the \( y \)-axis.
Mathematical Visualization
The ability to visualize mathematical concepts is a vital skill, especially when dealing with multivariable functions like \( f(x, y) = x^2 \). Mathematical visualization allows you to translate abstract equations into tangible images and shapes.
For instance, visualizing \( f(x, y) = x^2 \) involves seeing beyond the simple equation and recognizing how it translates into a parabolic cylinder in three-dimensional space. This entails understanding:
For instance, visualizing \( f(x, y) = x^2 \) involves seeing beyond the simple equation and recognizing how it translates into a parabolic cylinder in three-dimensional space. This entails understanding:
- The role of each variable in shaping the graph.
- How the absence of \( y \) in the equation reflects its continuous influence without directional change.
- The endless repetition across the \( y \)-axis, forming a surface that is uniform along this direction.