Chapter 9: Problem 9
Sketch the graph of the given parametric equations; using a graphing utility is advisable. Be sure to indicate the orientation of the graph. \(x=t^{3}-2 t^{2}, \quad y=t^{2}, \quad-2 \leq t \leq 3\)
Short Answer
Expert verified
The sketch shows a curve from (-16, 4) through (0, 0) and (0, 4) to (9, 9), with arrows indicating increasing t.
Step by step solution
01
Analyze the Parametric Equations
The given parametric equations are \( x = t^3 - 2t^2 \) and \( y = t^2 \). The range for parameter \( t \) is \(-2 \leq t \leq 3\). These equations will define the trajectory of a point (x, y) as the parameter \( t \) changes. The goal is to sketch the graph showing how x and y vary as \( t \) progresses from -2 to 3.
02
Calculate Key Points
Calculate the key points by substituting strategic values of \( t \) within the given range into the parametric equations.- For \( t = -2 \): \( x = (-2)^3 - 2(-2)^2 = -8 - 8 = -16 \), \( y = (-2)^2 = 4 \) gives the point (-16, 4)- For \( t = 0 \): \( x = 0^3 - 2(0)^2 = 0 \), \( y = 0^2 = 0 \) gives the point (0, 0)- For \( t = 2 \): \( x = 2^3 - 2(2)^2 = 8 - 8 = 0 \), \( y = 2^2 = 4 \) gives the point (0, 4)- For \( t = 3 \): \( x = 3^3 - 2(3)^2 = 27 - 18 = 9 \), \( y = 3^2 = 9 \) gives the point (9, 9)
03
Identify Changes in Graph Behavior
Observe the behavior of x and y as \( t \) changes. Notice x starts at -16 when \( t = -2 \) and increases or decreases depending on the parabola formed by \( t^3 - 2t^2 \). Also, y is always positive, as it's given by \( y = t^2 \). This indicates any reversal in direction must involve an x-orientation change.
04
Sketch the Graph
Using graphing software or manually, plot the points found in Step 2. The graph should begin at approximately \((-16, 4)\), pass through \((0, 0)\) and \((0, 4)\), and continue to \((9, 9)\). Connect these points smoothly to form a path described by these parametric equations.
05
Indicate Orientation
The orientation is determined by the progression of \( t \) from -2 to 3. Arrowheads should be added to the graph along the trajectory to indicate this direction, demonstrating how the graph evolves as \( t \) increases.
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.
Graph Sketching
Graph sketching involves illustrating the path a function or relation takes on a coordinate system. When sketching the graph of parametric equations, both the x and y coordinates are expressed in terms of a parameter, usually denoted as \( t \). Hence, the graph is sketched by plotting points corresponding to various values of \( t \). It is a bit like connecting dots.
To sketch the graph accurately:
Through this method, the path of movement for the parametric equations is revealed as a continuous curve. Observing how these points connect helps in visualizing the relationship between x and y, influenced by the changes in \( t \).
To sketch the graph accurately:
- Identify a range for \( t \); in our problem, this range is from -2 to 3.
- Substitute key values of \( t \) into the parametric equations to find corresponding pairs of \( (x, y) \) coordinates.
- Plot the points found. For example, points like (-16, 4), (0, 0), (0, 4), and (9, 9) can be plotted using the parametric equations.
- Connect these points with a smooth line, which represents the trajectory of the point as \( t \) evolves.
Through this method, the path of movement for the parametric equations is revealed as a continuous curve. Observing how these points connect helps in visualizing the relationship between x and y, influenced by the changes in \( t \).
Orientation in Graphs
Understanding orientation in graphs is about understanding the direction of travel along the path of a graph as the parameter, \( t \), changes. It’s kind of like direction arrows on a map, showing you 'where to go'. For parametric plots, this involves observing how the curve is traversed as \( t \) increases.
To determine the orientation:
Understanding the orientation helps in differentiating parametric graphs from mere collections of points by showing the path the graph takes as \( t \) progresses.
To determine the orientation:
- Track how your plotted points progress as \( t \) goes from the minimum to its maximum value.
- Add arrows on the graph to emphasize the direction from one point to the next. For example, you start at \((-16, 4)\) and end at \((9, 9)\).
- Observe if there are any reversals or loops; this is essentially determined by changes in the signs or values of \( x \) or \( y \).
Understanding the orientation helps in differentiating parametric graphs from mere collections of points by showing the path the graph takes as \( t \) progresses.
Parametric Plotting
Parametric plotting is a method for graphing equations where both x and y are expressed in terms of a third variable, often called the parameter \( t \). This allows for more flexible and dynamic graphs that can describe complex paths and movements.
Here’s how parametric plotting works:
This technique is especially useful for illustrating paths like curves, loops, or other complex shapes, where direct x-y plotting would be challenging. It's a powerful tool to understand how systems behave under changing conditions.
Here’s how parametric plotting works:
- Assign a range of values to \( t \), allowing you to compute corresponding x and y values using the given parametric equations.
- Calculate several \( (x, y) \) pairs within this range. Each pair corresponds to a specific value of \( t \). E.g., when \( t = -2 \), \( x = -16 \) and \( y = 4 \).
- Plotting these points on a graph reveals the path the equations describe, showing how x and y change over time.
- Parametric plotting can reveal patterns, symmetry, and other geometric properties that aren’t immediately obvious from separate x or y functions.
This technique is especially useful for illustrating paths like curves, loops, or other complex shapes, where direct x-y plotting would be challenging. It's a powerful tool to understand how systems behave under changing conditions.