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alias
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Homework Statement
Describe the region of R^3 that is represented by:
Homework Equations
x^2 + y^2 + z^2 > 2z
The Attempt at a Solution
I'm not sure what to do with this at, especially at z=0 and z=2
SammyS said:Where do you find any point (x, y) that satisfies x^2 + y^2 + (z-1)^2 > 1 , relative to the set of points that satisfy x^2 + y^2 + (z-1)^2 = 1 ?
alias said:for the equation, a point inside the sphere would be (1/2, 0, 1)
.5^2 + 0^2 + (1-1)^2 = .25
outside the the sphere would be (1,1,1)
1^2 + 1^2 + (1-1)^2 = 2
alias said:\sqrt{(x-0)^2 + (y-0)^2 + (z-1)^2}
is the distance between two points, (0, 0, -1) and any point (x,y,z)
but I still don't understand the constraint on x, y, and/or z.
Yes. TYPO !HallsofIvy said:I'm afraid SammyS rather confused things when he asked about "(x, y)" in post #6.
...
Actually, it's the distance between two points, (0, 0, 1) and any point (x,y,z). In other words, it's the distance from the center of your sphere to any point (x,y,z).alias said:\sqrt{(x-0)^2 + (y-0)^2 + (z-1)^2}
is the distance between two points, (0, 0, -1) and any point (x,y,z)
but I still don't understand the constraint on x, y, and/or z.
alias said:The distance between (0,0,1) and (x,y,z) is greater than 1. I'm not sure about the relation to the sphere though.
If the distance from (0,0,1) is 1, the point (x,y,z) is on the surface of the sphere. If that distance is greater than 1 doesn't the point lies outside the sphere?alias said:The distance from (0,0,1) to any point on the surface of the sphere is 1.
How does this relate to the inequality with the radius?
SammyS said:If the distance from (0,0,1) is 1, the point (x,y,z) is on the surface of the sphere. If that distance is greater than 1 doesn't the point lies outside the sphere?
If [itex](x)^2 + (y)^2 + (z-1)^2>1\,,[/itex] what does that say about [itex]\sqrt{(x-0)^2 + (y-0)^2 + (z-1)^2}\,?[/itex]
R^3, or "R-cubed", refers to the three-dimensional Cartesian coordinate system in mathematics. It is composed of the x, y, and z axes, which intersect at the origin (0,0,0) to form a three-dimensional space.
A sphere in R^3 is a perfectly round three-dimensional shape with all points equidistant from the center. It can be described using the equation x^2 + y^2 + z^2 = r^2, where r is the radius of the sphere.
An inequality in R^3 is a mathematical expression that compares two quantities using symbols such as <, >, ≤, or ≥. It represents a range of values rather than a specific value.
The region of R^3, sphere with inequality, can be described as the set of all points within or on the surface of a sphere with a given radius, which satisfy a specific inequality. This can be visualized as a three-dimensional shape with a curved surface and a hollow interior.
R^3, sphere with inequality is useful in scientific research for modeling real-world phenomena that are three-dimensional in nature. It allows scientists to define and study a specific region within a three-dimensional space, which can help in understanding and predicting complex systems and processes. It is commonly used in fields such as physics, engineering, and computer science.