Items tagged with sphere

   Consider a surface of the unit sphere about the origin, intersecting the volume of the cube [-a..a,-a..a,-a..a] 0<a<1.  What is the best Maple method to plot this surface with a direct mapping, that is without use of implicit plotting over a volume or rejecting grid points?

Dear all,

I would like to find a way to make the reflection of a spherical wave inside a tube (a cylinder). You have herafter an exemple of a sphere increasing inside a tube, but without the reflections...

 

Any idea how to do this?

Thanks a lot for your help.

 

Hi all,

 

I am generating a sphere with increasing radius that interacts at some point with a plan, just like this:

I would like to find a way to make the sphere "wave" (I agree this is not a wave...) reflected by the plan as in a mirror.

How could I do that ?

Thanks a lot for your help.

B

Im trying to draw a shpere but it always saying: 

Error, (in plot3d) unexpected option: z = -2 .. 2


this is the equation: x^2+y^2+z^2-4=0

i'm writing this way

plot3d(x^2+y^2+z^2-2^2, x = -2 .. 2, y = -2 .. 2, z = -2 .. 2)


what should I do? this is my first time with this software

 

best from Brazil,
Nina

Is there an elegant way to plot in 3d only the portion of the function f(x,y)=sqrt(25-x^2-y^2) for which 9 <= x^2+y^2 <= 16 ? I'm looking for a nice plot that shows it against the whole sphere with radius 5, so that it's clear which part of the sphere is cut out.

@Carl Love 

i guess that it is this.

actually my goal is 

drawing

 tangent vector field on even-dimensional n-spheres

can vector field plot do this too?

if start from draw vector field on a sphere

 

i find that intersectplot under plot, 

is it possible for fieldplot has this

 

such as the graph in wiki

https://en.wikipedia.org/wiki/Hairy_ball_theorem

 

I use Mathematica. This code finds integer points on the sphere

(x-2)^2 + (y-4)^2 + (c-6)^2 =15

and select two of them so that distance of two this points equal to 4.

ClearAll[a, b, r, c];
a = 2;
b = 4;
c = 6;
r = 15; ss =
Subsets[{x, y, z} /.
Solve[{(x \[Minus] a)^2 + (y \[Minus] b)^2 + (z \[Minus] c)^2 ==
r^2, x != a, y != b, z != c, x y z != 0}, {x, y, z},
Integers], {2}];
t = Select[ss, And @@ Unequal @@@ Subsets[Flatten[#], {2}] &];
Length[t]
Select[ss, Apply[EuclideanDistance, #] === 4 &]

 

and this code select four points on the shere so that none of three points make a right triangle

ClearAll[a, b, r, c];
a = 2;
b = 4;
c = 6;
r = 15;
ss = Subsets[{x, y, z} /.
Solve[{(x - a)^2 + (y - b)^2 + (z - c)^2 == r^2, x != a, y != b,
z != c, x y z != 0, x > y}, {x, y, z}, Integers], {4}];
nonright =
Pick[ss, (FreeQ[#, \[Pi]/2] &) /@ ({VectorAngle[#2 - #1, #3 - #1],
VectorAngle[#1 - #2, #3 - #2],
VectorAngle[#1 - #3, #2 - #3]} & @@@ ss)];
Select[nonright, (12 == Length[Union @@ #] &)]

 I am looking for a  procedure in Maple.  I have some problems with this sphere. For example:

Choose four points so that 12 coordinates difference and it makes a square.

Can your code improve with sphere?

The downloaded worksheet below displays 3 points on the unit sphere which define a solid angle with a triangular face. The sides of the solid angle's are red arcs on the surface of the sphere and red radii which outline the planar sides within the sphere.

Three questions:

1. Is there a way to make the surfaces of the solid triangle more apparent by filling them with color?

2. Is there a way to calculate the area of the face on the surface of the sphere?

3. Is there a way to calculate the volume of the solid triangle?

 

Download Mechanics;_irregular_solid_angle.mw

This post is related to the question. There were  proposed two ways of finding the volume of the cutted part of a sphere in the form of a wedge.  Here the procedure is presented that shows the rest of the sphere. Parameters procedure: R - radius of the sphere, H1 - the distance the first cutting plane to the plane  xOy,  H2 -  the distance the second cutting plane to the plane  zOy. Necessary conditions:  R>0,  H1>=0,  H2>=0,  H1^2+H2^2<R^2 . For clarity, different surfaces are painted in different colors.

restart;

Pic := proc (R::positive, H1::nonnegative, H2::nonnegative)

local A, B, C, E, F;

if R^2 <= H1^2+H2^2 then error "Should be H1^(2)+H2^(2)<R^(2)" end if;

A := plot3d([R*sin(theta)*cos(phi), R*sin(theta)*sin(phi), R*cos(theta)], phi = arctan(sqrt(-H1^2-H2^2+R^2), H2) .. 2*Pi-arctan(sqrt(-H1^2-H2^2+R^2), H2), theta = 0 .. Pi, color = green);

B := plot3d([R*sin(theta)*cos(phi), R*sin(theta)*sin(phi), R*cos(theta)], phi = -arctan(sqrt(-H1^2-H2^2+R^2), H2) .. arctan(sqrt(-H1^2-H2^2+R^2), H2), theta = 0 .. arccos(sqrt(R^2-H2^2-H2^2*tan(phi)^2)/R), color = green);

C := plot3d([R*sin(theta)*cos(phi), R*sin(theta)*sin(phi), R*cos(theta)], phi = -arctan(sqrt(-H1^2-H2^2+R^2), H2) .. arctan(sqrt(-H1^2-H2^2+R^2), H2), theta = arccos(H1/R) .. Pi, color = green);

E := plot3d([r*cos(phi), r*sin(phi), H1], phi = -arccos(H2/sqrt(R^2-H1^2)) .. arccos(H2/sqrt(R^2-H1^2)), r = H2/cos(phi) .. sqrt(R^2-H1^2), color = blue);

F := plot3d([H2, r*cos(phi), r*sin(phi)], phi = arccos(sqrt(-H1^2-H2^2+R^2)/sqrt(R^2-H2^2)) .. Pi-arccos(sqrt(-H1^2-H2^2+R^2)/sqrt(R^2-H2^2)), r = H1/sin(phi) .. sqrt(R^2-H2^2), color = gold);

plots[display](A, B, C, E, F, axes = none, view = [-1.5 .. 1.5, -1.5 .. 1.5, -1.5 .. 1.5], scaling = constrained, lightmodel = light4, orientation = [60, 80]);

end proc:

 

Example of use:

Pic(1,  0.5,  0.3);

                             

 

 

I have drawn a 3d plot of a sphere in maple, but when I try to export this one in an .eps file, only the coordinate system of the plot is shown, but not the colourful plot. The export works if I use jpg and similar file types, but not with .eps, does anybody know if there is a way out of this problem?

I have 3 column vectors:

phi contains the number of radians from the North Pole

theta contains the number of radians from the Greenwich meridian

D contains number data corresponding to the point (phi,theta) on the sphere.

 

How do I plot:

a) a contour plot on the surface of the sphere where each point at (phi, theta) has a corresponding data value D?

b) a plot where the height above the surface at (phi, theta) is some linear function of D such as radius*D*constant?

I have a list L. In geom3d, I want to write all tangent of plane of the spherefrom L. But I don't know. I only write one point . I tried 

> restart:

with(geom3d):

L:=[[-5, -5, 8], [-5, -1, 10], [-5, 3, 10], [-5, 7, 8], [-5, 8, -5], [-5, 8, 7], [-5, 10, -1], [-5, 10, 3], [-1, -5, 10], [-1, 7, 10], [-1, 10, -5], [-1, 10, 7...

restart;with(geom3d):

point(M,1,2,1):

plane(P,x+y-3=0,[x,y,z]):

plane(Q,2*x-2*y+z-1=0,[x,y,z]):

line(d,[1+2*t,1-t,t],t):

n:=NormalVector(P):

line(Delta,[M,n],t):

Eq:=Equation(Delta):

intersection(N,d,P):

coordinates(N):

Please write for me a code for the following problem.

Let (S): x^2 + y^2 + z^2 -2*x +2*z + 1 = 0 be a sphere and M(1, 2, -1), N(3, 1, -1) be two points. Find the coordinates of the point K lies on the sphere (S) such that the triangle KHN has minimum area. 

Thank you very much.

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