Question

Find two different sets of parametric equations for the rectangular equation. $$ y=x^{3} $$

Short answer

First set of parametric equations are: \( x = t \) and \( y = t^{3} \). Second set of parametric equations are: \( x = \sqrt{t} \) and \( y = t^{\frac{3}{2}} \).

Step-by-step solution

Construct First Set of Parametric Equations

For the first set, the parameter, \( t \), can be chosen to be equivalent to \( x \). So the parametric equations become: \( x = t \) and \( y = t^{3} \).

Construct Second Set of Parametric Equations

For the second set, a different relationship can be established. The parameter, \( t \), can be chosen such that \( t = x^{2} \). Plugging this change of variable into the original equation yields: \( x = \sqrt{t} \) and \( y = (\sqrt{t})^{3} = t^{\frac{3}{2}} \).

Key concepts

Rectangular Equation

In the realm of algebra and calculus, a rectangular equation is one that is expressed in terms of x and y, which are the rectangular coordinates in a two-dimensional plane. The given exercise presents a simple rectangular equation,

\[ y = x^3 \]

This is a fundamental example of how an equation can represent a curve in a Cartesian coordinate system. The graph of this equation is a curve with a distinctive 'S' shape, known as a cubic parabola. One of the crucial skills in calculus is to be able to take such an equation and explore it through different lenses, such as with parametric equations.

Understanding rectangular equations is key in calculus as it lays the foundation for describing geometric shapes, solving optimization problems, and analyzing the behavior of functions.

Calculus

When discussing calculus, it is a branch of mathematics that studies continuous change and consists of two major areas: differential calculus and integral calculus. Differential calculus concerns itself with the concept of a derivative, which represents the rate of change of a quantity. Integral calculus, on the other hand, deals with the concept of an integral, used to find areas under curves and the accumulated quantities.

The exercise at hand involves an element of calculus called parametrization. Parametrization is a powerful tool used to represent algebraic equations, such as the rectangular equation given, in terms of a third variable, typically called a parameter. This approach can significantly simplify computations in certain cases, for instance, when one needs to calculate the length of a curve or the area under a curve, or when analyzing motion along a path described by the curve.

Variable Transformation

The concept of variable transformation, also known in some cases as reparameterization, is about changing the description of a mathematical object by using different variables or parameters. In the exercise, this is illustrated by creating sets of parametric equations from a rectangular equation by introducing a new variable,

\( t \).

In the first step of the solution, a direct variable transformation was used by setting \( t = x \), which led to a straightforward pair of parametric equations. The second step involves a more creative transformation: \( t = x^2 \), which allowed the derivation of a new set of parametric equations. Understanding variable transformation is crucial for students as it provides a versatile technique that can be applied to problems in physics, engineering, and computer graphics where changing the way we describe a problem can make it easier to solve.