How to parametrize a sphere?
Understand the Problem
The question is asking how to define a sphere using a set of parameters, typically involving mathematical equations using spherical coordinates. It aims to express the surface of a sphere in terms of angles and radii.
Answer
The sphere is defined by \( r = R \), \( 0 \leq \theta \leq \pi \), \( 0 \leq \phi < 2\pi \).
Answer for screen readers
The surface of a sphere of radius ( R ) in spherical coordinates is defined by:
- ( r = R )
- ( 0 \leq \theta \leq \pi )
- ( 0 \leq \phi < 2\pi )
Steps to Solve
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Understanding spherical coordinates Spherical coordinates are used to define points in three-dimensional space using three parameters: the radius ( r ), the polar angle ( \theta ), and the azimuthal angle ( \phi ). The parameters are related to Cartesian coordinates as follows:
- ( x = r \sin(\theta) \cos(\phi) )
- ( y = r \sin(\theta) \sin(\phi) )
- ( z = r \cos(\theta) )
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Defining a sphere To define a sphere in spherical coordinates, we need to express the relationship between ( r ), ( \theta ), and ( \phi ). The points on the surface of a sphere of radius ( R ) can be represented as:
- ( r = R )
- ( 0 \leq \theta \leq \pi ) (from pole to pole)
- ( 0 \leq \phi < 2\pi ) (around the equator)
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Equation of the sphere The surface of the sphere can also be expressed in Cartesian coordinates through the equation: $$ x^2 + y^2 + z^2 = R^2 $$ This relates back to the spherical coordinates by substituting the defined equations for ( x ), ( y ), and ( z ).
The surface of a sphere of radius ( R ) in spherical coordinates is defined by:
- ( r = R )
- ( 0 \leq \theta \leq \pi )
- ( 0 \leq \phi < 2\pi )
More Information
A sphere is a perfectly symmetrical object in three dimensions. The concept of a sphere is important in fields such as physics, engineering, and computer graphics. Spherical coordinates are particularly useful in situations where problems involve symmetry around a point.
Tips
- Confusing the angles ( \theta ) and ( \phi ). Remember, ( \theta ) is usually the angle from the vertical (z-axis) and ( \phi ) is the angle from the horizontal (x-axis).
- Not considering the ranges for ( \theta ) and ( \phi ). The incorrect application of ranges can lead to undefined or irrelevant points not on the sphere.
