Chapter 5: Problem 2
True or False? Function \(\mathbf{r}(t)=\mathbf{a}+t(\mathbf{b}-\mathbf{a})\), where \(0 \leq t \leq 1\), parameterizes the straight-line segment from \(\mathbf{a}\) to \(\mathbf{b}\).
Short Answer
Expert verified
True. The function correctly parameterizes the straight-line segment from \(\mathbf{a}\) to \(\mathbf{b}\).
Step by step solution
01
Understanding the Function
The function given is \(\mathbf{r}(t)=\mathbf{a}+t(\mathbf{b}-\mathbf{a})\). This form is a linear interpolation between the points \(\mathbf{a}\) and \(\mathbf{b}\). The parameter \(t\) determines the position along the line segment, where \(t=0\) corresponds to \(\mathbf{a}\) and \(t=1\) corresponds to \(\mathbf{b}\).
02
Analyzing the Parameter Range
The parameter \(t\) is defined such that \(0 \leq t \leq 1\). This range ensures that the function \(\mathbf{r}(t)\) only traces the path from \(\mathbf{a}\) to \(\mathbf{b}\) without extending beyond these points.
03
Considering the Geometrical Interpretation
The expression \(\mathbf{a} + t(\mathbf{b} - \mathbf{a})\) describes a point on the line passing through \(\mathbf{a}\) and \(\mathbf{b}\). As \(t\) varies from 0 to 1, the function traces a path from \(\mathbf{a}\) directly to \(\mathbf{b}\). This is the definition of a line segment.
04
Conclusion on the Parameterization
Given that \(\mathbf{r}(t)\) represents a straight-line interpolation between \(\mathbf{a}\) and \(\mathbf{b}\), and \(t\) only takes values between 0 and 1, the function correctly parameterizes the straight-line segment from \(\mathbf{a}\) to \(\mathbf{b}\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Linear Interpolation
Linear interpolation is a method used to find a value within two known points. In the context of the function \(\mathbf{r}(t)=\mathbf{a}+t(\mathbf{b}-\mathbf{a})\), it is utilized to determine any point along the straight line that connects these two points, \(\mathbf{a}\) and \(\mathbf{b}\).
When you think about linear interpolation, imagine traveling from one city to another. If \(\mathbf{a}\) is your starting city and \(\mathbf{b}\) is your destination, the parameter \(t\) acts like a progress tracker indicating how far along the route you are at any given time.
The important aspects of linear interpolation involve:
When you think about linear interpolation, imagine traveling from one city to another. If \(\mathbf{a}\) is your starting city and \(\mathbf{b}\) is your destination, the parameter \(t\) acts like a progress tracker indicating how far along the route you are at any given time.
The important aspects of linear interpolation involve:
- Finding intermediate points: By adjusting the value of \(t\) between 0 and 1, you can locate any point on the line connecting \(\mathbf{a}\) and \(\mathbf{b}\).
- Maintaining a straight path: Since only a linear function of \(t\) is involved, the path between the points is straight.
Vector Functions
Vector functions extend the concept of functions to include multiple dimensions. They map a scalar input, often time \(t\), to a vector output. In our function \(\mathbf{r}(t)=\mathbf{a}+t(\mathbf{b}-\mathbf{a})\), \(\mathbf{r}(t)\) is a vector function that takes \(t\) and returns a vector that represents a position in space.
Understanding vector functions involves recognizing the components they include. Each vector is made up of multiple elements, corresponding to the dimensions of the space it exists in:
Understanding vector functions involves recognizing the components they include. Each vector is made up of multiple elements, corresponding to the dimensions of the space it exists in:
- Representation of dimensions: In two dimensions, a vector might have an \(x\) and \(y\) component. In three dimensions, it could have \(x\), \(y\), and \(z\).
- Function mapping: The vector function maps each \(t\) to a unique point in the space, describing a curve or path as \(t\) changes.
Parameterization of Curves
Parameterization is a way of expressing the coordinates of points on a curve using parameters. In the case of the line segment from \(\mathbf{a}\) to \(\mathbf{b}\), the function \(\mathbf{r}(t)=\mathbf{a}+t(\mathbf{b}-\mathbf{a})\) parameterizes this straight path by using \(t\) as the parameter.
This method allows for:
This method allows for:
- Controlled representation: By varying \(t\) over a specific range, you describe the entire set of points on the line segment.
- Avoiding points beyond the curve: Since \(t\) is confined between 0 and 1, it ensures that the parameterization only covers the part from \(\mathbf{a}\) to \(\mathbf{b}\), not beyond.