In Exercises 1–8, parametric equations and a value for the parameter t are given. Find the coordinates of the point on the plane curve described by the parametric equations corresponding to the given value of t. x = (60 cos 30°)t, y = 5 + (60 sin 30°)t − 16t²; t = 2
Table of contents
- 0. Review of College Algebra4h 45m
- 1. Measuring Angles40m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
9. Polar Equations
Polar Coordinate System
Problem 77
Textbook Question
Find two different sets of parametric equations for y = x² + 6.
Verified step by step guidance1
Recall that a parametric equation expresses both x and y in terms of a third variable, usually t. Our goal is to find expressions for x(t) and y(t) such that y(t) = (x(t))^2 + 6.
For the first set, choose a simple parameterization for x, for example, let x = t. Then substitute into the original equation to get y = t^2 + 6. So the first set is: \(x = t\), \(y = t^2 + 6\).
For the second set, choose a different parameterization for x, such as x = 2t. Substitute into the original equation to find y: \(y = (2t)^2 + 6 = 4t^2 + 6\). So the second set is: \(x = 2t\), \(y = 4t^2 + 6\).
Verify that both sets satisfy the original equation by eliminating the parameter t. For the first set, since \(x = t\), substituting back gives \(y = x^2 + 6\). For the second set, since \(x = 2t\), then \(t = \frac{x}{2}\), and substituting into y gives \(y = 4\left(\frac{x}{2}\right)^2 + 6 = x^2 + 6\).
Thus, both parametric forms represent the same parabola \(y = x^2 + 6\), but with different parameterizations of x in terms of t.
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
2mPlay a video:
0 Comments
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Parametric Equations
Parametric equations express the coordinates of points on a curve as functions of a third variable, usually t. Instead of y as a function of x, both x and y are defined in terms of t, allowing more flexible representations of curves.
Recommended video:
Parameterizing Equations
Representing Parabolas Parametrically
A parabola like y = x² + 6 can be represented parametrically by setting x = t and y = t² + 6. Alternative parameterizations can involve different expressions for x and y in terms of t, as long as they satisfy the original equation.
Recommended video:
Eliminating the Parameter
Multiple Parametric Forms
A single curve can have infinitely many parametric representations by choosing different parameter functions. For example, using x = 2t or x = t - 1 with corresponding y values still trace the same parabola, illustrating the flexibility of parametric forms.
Recommended video:
Parameterizing Equations
Related Videos
Related Practice
Textbook Question
602
views
