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Ch. 5 - Complex Numbers, Polar Coordinates and Parametric Equations
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601당신이 사용하는 게 아니라요?교과서 변경
5장, 문제 77

Find two different sets of parametric equations for y = x² + 6.

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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.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

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.
추천 영상:
08:02
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.
추천 영상:
05:59
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.
추천 영상:
08:02
Parameterizing Equations