Cylindrical Coordinate Inequalities: Half-Cylinder and Quarter Cone/Paraboloid

  • Thread starter Thread starter fball558
  • Start date Start date
  • Tags Tags
    Cylindrical
fball558
Messages
143
Reaction score
0
cylindrical cordinace??

Homework Statement



this is a two part question and is multiple choice

part 1
Determine the type of the solid described by the given inequalities.
0 ≤ r ≤ 4, - pi≤ θ ≤ pi, -sqrt(16 − r^2) ≤ z ≤ sprt(16 − r^2)
a half-cylinder
a cylinder
a half-sphere
a sphere
a parallelepiped

part 2

Determine the type of the solid described by the given inequalities.
0<= theta <= pi/2 r <= z <= 5

a quarter of a cone
a half-cone
a quarter of a paraboloid
a half-paraboloid
a parallelepiped

graphing in cylindrical confuses me. any help on how to attach these would be great.
by looking at the second on i would assume it would be one the quarter somethings just because it is giong from 0 to pi/2 but don't know if that is right and if so how to tell the diff between cone or paraboloid??
 
Physics news on Phys.org


Do you know how to graph polar coordinate in two dimensions? If you can graph a point with polar coordinates (r, \theta) in the plane, cylindrical coordinates in three dimensions aren't much more complicated. The third coordinate is a z coordinate.

Also, do you know the formulas for converting from Cartesian (or rectangular) coordinates to polar, and vice versa?
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top