Chapter 4: Problem 43
Describe in words the curve represented by the parametric equations $$x=3+t^{3}, \quad y=5-t^{3}$$
Short Answer
Expert verified
The curve is a straight line described by \(y = 8 - x\).
Step by step solution
01
Understand Parametric Equations
The given parametric equations describe the relationship between two variables, x and y, in terms of a third variable, t. These equations are: \(x = 3 + t^3\) and \(y = 5 - t^3\). The variable t is known as the parameter, and as it varies, it traces out a curve in the xy-plane.
02
Analyzing x and y Equations
Let's analyze each equation. For \(x = 3 + t^3\), as t changes, the value of x increases or decreases depending on t. Similarly, for \(y = 5 - t^3\), as t changes, y also varies correspondingly.
03
Eliminate Parameter t
To find the relation between x and y, eliminate the parameter t. From \(x = 3 + t^3\), we solve for \(t^3 = x - 3\). Similarly, from \(y = 5 - t^3\), we solve for \(t^3 = 5 - y\). Equating the two, we find: \(x - 3 = 5 - y\) or rearranging gives \(y = 8 - x\).
04
Interpret the Resulting Equation
The equation \(y = 8 - x\) is a linear equation representing a line with a slope of -1 on the xy-plane. It is a straight line that has an inverse relationship between x and y.
05
Describe the Curve
Since the parametric form can be continuously mapped to a straight line, the curve described by the given parametric equations is a line. The line passes through specific points in the plane defined by the equations, but overall it forms the line \(y = 8 - x\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Parametric Equations Analysis
Parametric equations help us understand how a curve or a path is traced out by varying a parameter. In the given exercise, we have two equations: \(x = 3 + t^3\) and \(y = 5 - t^3\). Here, \(t\) is the parameter, and it plays a crucial role in plotting the path of the curve.
As \(t\) changes its value, the equations determine the corresponding x and y coordinates. This means each point on the curve is defined by a particular value of t. It's like having a set of instructions that tell you where to go as t changes.
As \(t\) changes its value, the equations determine the corresponding x and y coordinates. This means each point on the curve is defined by a particular value of t. It's like having a set of instructions that tell you where to go as t changes.
- For positive values of \(t\), \(x\) becomes larger than 3 while \(y\) decreases from 5.
- For negative values of \(t\), \(x\) becomes smaller than 3 and \(y\) increases above 5.
Parameter Elimination
To establish a connection directly between \(x\) and \(y\), we need to eliminate the parameter \(t\). By taking the given equations \(x = 3 + t^3\) and \(y = 5 - t^3\), we can determine the relationship between x and y.
Solve for \(t^3\) in both equations:
After simplifying, the equation \(y = 8 - x\) is derived, showing a direct relationship excluding the parameter \(t\). Parameter elimination is essential in finding a familiar geometry form, such as a line or curve, from parametric equations.
Solve for \(t^3\) in both equations:
- From \(x = 3 + t^3\), we get \(t^3 = x - 3\).
- From \(y = 5 - t^3\), we find \(t^3 = 5 - y\).
After simplifying, the equation \(y = 8 - x\) is derived, showing a direct relationship excluding the parameter \(t\). Parameter elimination is essential in finding a familiar geometry form, such as a line or curve, from parametric equations.
Relationship Between x and y
Upon eliminating the parameter \(t\), we find a straightforward relationship between x and y in the form of \(y = 8 - x\). This equation represents a linear relationship, which is interpreted as a straight line when graphed on the xy-plane.
Here's what to note about this line:
Here's what to note about this line:
- The slope of the line is \(-1\), indicating that as \(x\) increases, \(y\) decreases. This is an inverse relationship.
- The line crosses the y-axis at \(y = 8\), which is the intercept.
- Every unit increase in x results in a unit decrease in y, maintaining the balance between x-offset and y-offset, which confirms the inverse nature of the relationship.