# Items tagged with curvecurve Tagged Items Feed

### How to plot this in Maple...

May 29 2016
2 2

Hi,

I am having trouble in plotting the following surface (it is a quite complicated expression, but should be fine).

OwnSurface := [-Re(arctan(exp(I*Pi*(1/4))*(u^2+v^2)^(1/2)))-(1/2)*ln((1+(u^2+v^2)^2)^(1/2)), -arctan(1/((2*(u^2+v^2))^(1/2)-1))+7*Pi*(1/4), (1/8)*ln(u^2+v^2-(2*(u^2+v^2))^(1/2)+1)-(1/8)*ln(u^2+v^2+(2*(u^2+v^2))^(1/2)+1)-(1/4)*arctan(1/((2*(u^2+v^2))^(1/2)+1))+(1/4)*arctan(1/((2*(u^2+v^2))^(1/2)-1))];

plot3d(OwnSurface, u = -.4 .. .4, v = -.4 .. .4, labels = [x1, x2, x3]);

The only thing maple does is plotting a box with a diagonal line. How can I fix this?

### Plotting Szego curve...

May 13 2016
0 2

I want to plot a curve of the form |z*e^(1-z)| = 1 (the Szego curve). I am not sure how to call complexplot() to make this happen. Just calling complexplot(abs(z*exp(1-z)) = 1) does not work, and I don't know what else to specify. Any help?

### Spiral around the curve...

March 15 2016 Maple 15
4
1

Spiral (equidistant) around the curve.  In this case, a spiral around the spiral.
So without any sense.
spiral_around_curve.mw

If we re-save the animation with the program Easy GIF Animator, its size is reduced by about 10 times, and sometimes much more.

### Cumulative frequency in Maple?...

January 31 2016
1 5

Hello I have this assignment. I will translate it (because it is not english)

This is the assignment: [IMG]http://i68.tinypic.com/2cgoby9.jpg[/IMG]

(if u cant click on the above link, then u can see it here http://tinypic.com/view.php?pic=2cgoby9&s=9)

So it says:

-------

In an examination of young pigs' birth weight 853 newborn pigs were weighted. The weighting is shown in the table down below.

[0,5-0,7] [0,7-0,9] [0,9-1,1] [1,1-1,3] [1,3-1,5] [1,5-1,7] [1,7-1,9] [1,9-2,1] [2,1-2,3] -> WEIGHT in kg

[26]            [43]       [102]       [145]        [171]      [196]     [119]       [42]          [9]      --> number of pigs

Draw a cumulative frequency curve of the weighting and determine the kvartils.

SO I usually do this in Maple, but this time I did a matrix but nothing happened.. I dont know how I should draw this curve? Help please.

[IMG]http://i68.tinypic.com/2cgoby9.jpg[/IMG]

### Catmull-Rom spline curves...

January 19 2016
0 11

Hello,

I try to use a Catmull-Rom spline which has to match on several points.

I use a code extracted from the book "Geometry and curves with maple".

Here you can find an extract which is visible from google book :

I have slightly modified the initial procedure crom_2d. I didn't find the error in my procedure. May you help me to find the blocking point of my procedure ?

Here I attached my code:

CalculSplineMatmull-Rom.mw

Thank you for your help.

### Plot of Implicitly Defined 3D Curve...

January 10 2016
0 6

Suppose that we have the following curve on a unit sphere

r^2+z^2=1

phi=pi/3

-1<=z<=1

which is the implicit equation of a circle in "cylindrical coorinates" (r,phi,z) on the sphere.

How can I plot this curve without solving the implicit equation for r or z ?

Also, I don't want to make any parameterization.

### Showing Oriented Parametric Curve...

December 23 2015
3 25

Suppose I have the parametric equations of a circle

x=cost

y=sint

where t runs from 0 to 2*pi. How can I show the orientation of this parametric curve on a plot?

### Getting coordinates of curve points...

November 30 2015
0 2

Hello,

I'm a very new beginner, and I have a question about getting the data of a curve from a JPG, without using manual measures an too getting more accurate datas.

I wish to fit the curve with a model. The JPG joined, from EU 2015, is about human thermoregulation. I still try to found a model with Mathematica but am uncertain seeing the result as illogic.

Did anyone write something to read curves from a JPG and get coordinates from these curves ? In the JPG, the curve is above, as an 'U'.

Thanks for your advice,

Milos.

### Points on the curve...

October 25 2015
1 2

How I can highlight p(1,1) and Q(2,4) on the curve f(x)=x^2?

October 11 2015
0 3

Vahid Borji

### Plot of a certain curve...

September 18 2015
1 2

I have the following code of a plot:

plot(
[
add(BS(bb[4], t, i, 3)*bb[1](i+1), i = 0..n),
add(BS(bb[4], t, i, 3)*bb[2](i+1), i = 0..n),
t = 0..1
],
color=red, axes=normal, scaling=constrained, numpoints=100, thickness=2
):

and I get the following error:

Error, (in BS) cannot determine if this expression is true or false: 0 <= t and t < .54901960784313725490196078431373

The problem is that, in the definition of BS, there are some conditions that depend on the variable t. It seems that Maple does not use a specific value of t when executing BS. My solution is to plot specific points, i.e.,

plot(
[
seq([add(BS(bb[4], h/5000, i, 3)*bb[1](i+1), i = 0..n),
add(BS(bb[4], h/5000, i, 3)*bb[2](i+1), i = 0..n)], h=0..5000)
],
color=red, axes=normal, scaling=constrained, numpoints=100, thickness=2
):

Can this be done in a more elegant way?

### Polynomial intersection error...

September 16 2015
1 5

Hi, I'm new to Maple and have been trying to solve the below curve intersection. But the answer I am getting from Maple is incorrect and does not tally with the plot when drawn on excel, am I doing something wrong ???  (the intersect should be around x=93.9)

restart;
eq1:=y=86:
eq2:=y=-0.0000054527x^3+0.010903836x^2+0.0714244709x+74.18816:
sol:=solve({eq1,eq2},{x,y});

### Natural parametrization of curve...

September 06 2015
0 15

Let a piecewise-linear curve be defined by a listlist. For example,

LL := [[1.1, 2.04], [1.97, 4.04], [2.96, 2.97], [4.5, 6.4], [5.08, 7.21], [1.1, 4.04], [1.1, 2.04]]:
plot(LL);

How to find its natural parametrization in Maple? A procedure is desired. See Wiki for info.

### Area under implicitly defined curve...

August 16 2015
3 4

Hi,

I have a small problem. I want to findout area under a curve. I got the plot from solving a partial differential equation. I want to find out area under the curve with out using interpolation. Are there any methods to find this.

here i enclose the method i have done.

Es := 0.117108e12:
Ef := 0.78125e11:
l := 0.150e-6:
s := 0.500000e-3:
f := 0.5898334197e-6:
o := 0.9e-5:
d := 0.10e-17:
cb := 0.1e7/(19.9):
c := l*f/(d*cb):

PDE := diff(u(x, t), t)-(diff(u(x, t), x, x)) = 0:

with(plots):
with(plottools):
ys := -0.4245333333e-1:
IBC1 := {u(x, 0) = 0, (D[1](u))(0, t) = 0, (D[1](u))(1, t) = c}:
S1 := pdsolve(PDE, IBC1, numeric, time = t, timestep = 0.1e-2);

p2 := S1:-plot(t = .2525);

p3 := getdata(p2);

p3[3]:
co:=CurveFitting[PolynomialInterpolation](p3[3], x):
Area := int(co, x = x[1] .. x[2]):

So this is the procedure i used to find out, but can there be any other procedure to findout area directly from hte solution of PDE.

Thanks.

### How can i visualize conmplex functions in Maple?...

August 14 2015
3 5

Hello everybody,

my question concerns the visualizing possibilities of maple:

can maple visualize complex functions? (f(z): C->C)

If so, which possibilities do i have und what is the command for it? Maybe as a coulour diagram, as a vector field (f(x): R^2->R^2) , or as mapping of sets (e.g. curves, grids into new curves and curved lines)?

Thanks in advance

regards

Nikita

PS: I am using maple 18.

 1 2 3 4 Page 1 of 4
﻿