Chapter 14: Problem 5
Express the parametric equations as a single vector equation of the form \(\mathbf{r}=x(t) \mathbf{i}+y(t) \mathbf{j}\) or \(\mathbf{r}=x(t) \mathbf{i}+y(t) \mathbf{j}+z(t) \mathbf{k}\)\ $$x=3 \cos t, y=t+\sin t$$
Short Answer
Expert verified
\(\mathbf{r}(t) = 3\cos t\, \mathbf{i} + (t + \sin t)\, \mathbf{j}\).
Step by step solution
01
Understanding the Problem
We are given two parametric equations: \( x = 3 \cos t \) and \( y = t + \sin t \). Our goal is to express these parametric equations as a single vector equation.
02
Identify Components of the Vector Equation
To express the parametric equations as a vector equation of the form \( \mathbf{r} = x(t) \mathbf{i} + y(t) \mathbf{j} \), we identify \( x(t) = 3 \cos t \) and \( y(t) = t + \sin t \).
03
Formulate Vector Equation
Using the components identified, we can write the vector equation: \( \mathbf{r}(t) = 3 \cos t \mathbf{i} + (t + \sin t) \mathbf{j} \).
04
Verify the Vector Equation
Check that the vector equation correctly represents the parametric equations. \( x(t) = 3 \cos t \) corresponds to the \( \mathbf{i} \) component, and \( y(t) = t + \sin t \) corresponds to the \( \mathbf{j} \) component of the vector equation, verifying the solution is correct.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Parametric Equations
Parametric equations are a powerful mathematical tool used to describe a set of related quantities. In simple terms, they define a relationship between variables using a third variable, often called a parameter. For example, consider two parametric equations: \( x = f(t) \) and \( y = g(t) \). Here, \( t \) is the parameter, and \( f(t) \) and \( g(t) \) express \( x \) and \( y \) as functions of \( t \). This method is particularly useful for modeling curves, where the standard \( y=f(x) \) form does not suffice.
When using parametric equations:
When using parametric equations:
- Each parameter represents a different aspect of the system, allowing complex shapes and paths to be defined.
- They can help find intersections, tangents, and lengths of curves in calculus.
- Often used in physics and engineering to describe motion or paths.
Vector Equation
Vector equations combine parametric equations by using vectors to express them as a single statement. In the context of our example, each function, \( x(t) \) and \( y(t) \), becomes a component of a vector. That vector represents a point or a moving particle's position in a two-dimensional space. So, for our given equations, we express them in the form \( \mathbf{r}(t) = x(t) \mathbf{i} + y(t) \mathbf{j} \).
Here's the breakdown:
Here's the breakdown:
- \( \mathbf{i} \) and \( \mathbf{j} \) are unit vectors pointing in the direction of the x-axis and y-axis, respectively.
- The functions \( x(t) = 3 \cos t \) and \( y(t) = t + \sin t \) tell us how the x and y coordinates change as \( t \) varies.
- This form captures the trajectory of a point in the plane as \( t \) changes.
Trigonometric Functions
Trigonometric functions are a category of mathematical functions crucial in studying cycles and periodic phenomena. Handling periodic behavior, like that shown in \( x = 3 \cos t \), is a classic application of these functions. Let's break down their relevance:
- They are used to describe oscillations, rotations, and waves, essential in physics and engineering.
- In terms of parametric equations, trig functions help depict curved paths, such as circles or spirals.
- Functions like \( \cos t \) repeat values over intervals, making them predictable for cyclical movements.
Calculus Problem Solving
Calculus problem solving revolves around using derivatives and integrals to model and interpret real-world situations. Parametric equations and trigonometric functions are tools often employed in these scenarios. They allow for a more dynamic modeling of motion and change. Whether tracking a particle's motion along a path or analyzing forces in engineering, calculus provides the framework.
To effectively solve calculus problems:
To effectively solve calculus problems:
- Understand the relationships between the parametric expressions and the real-world phenomena they represent.
- Employ derivatives to study the rate of change, such as analyzing the velocity from displacement.
- Use vectors to simplify multidimensional problems, allowing a systematic approach to complex movement simulations.