# Items tagged with contourcontour Tagged Items Feed

### beta function vs. sine

March 21 2013 by Maple

Dear friends,

I am reporting with a brief comment concerning the integral int(1/(1+x^a), x=0..infinity) with a>=2 a real number. This was evaluated here.

Now Maple 15 (X86 64 LINUX) will quite happily compute this in its most simple form involving the sine when a is not a positive integer or a rational number. If it is, however, a beta function term results,...

### Maple Commands for exp function?

February 25 2013 by Maple

1

6

I'm trying to graph a contour map of this function: e^(y/x)

>with(plots)

>contourplot(e^(y/x),x=-3..3,y=-0.5..0.5)

I thought the contour map for this function would looks more like several lines intersects at the origin. But when I graph it on Maple, it doesn't looks like the graph I'm looking for.

Did I put in a wrong range?

### contour plot at value and at values

February 20 2013 by

0

2

Hi there i have function as:

f(B,F)=

where: F,B>0 and

,

such that:

h=B^2;

I need to plot the surface (contour plot) f(B,F) at 0 and -ve points i.e f(B,F)<0.

Thanks

### possible symbolic integration bug

December 09 2012 by

1

3

Dear friends,

I will present a series of commands for you to ponder that should speak for themselves.

> q := n -> int(1/(1-2^n*exp(I*theta*n))^2*2*I*exp(I*theta), theta=0..2*Pi);
2 Pi
/
|          2 I exp(theta I)
q := n ->  |      ------------------------ dtheta
|            n                2
/       (1 - 2  exp(theta n I...

### computing a residue

December 09 2012 by Maple

1

3

Dear friends,

I ran into another problem while using Maple to do residue calculus. The following call

residue(1/x^(1/3)/(x^2+2*x*cos(phi)+1), x=-exp(I*phi));

returns zero -- it does not recognize the residue. On the other hand, if I do a subsitution like this

subs(x=-exp(I*phi), 1/x^(1/3)/(x^2+2*x*cos(phi)+1));

followed by

convert(%, trig); simplify(%);

then I get a divide by zero error, which shows that the...

### more contour integration issues

December 09 2012 by Maple

1

9

Hello all,

I recently helped someone with a contour integration problem, you may find my calculation at the following link. It occurred to me to test this integral with Maple and Mathematica.

For example,

int(1/x^(1/3)/(x^2+2*x*cos(Pi/7)+1), x=0..infinity);

produces an unusable output from Mathematica. Maple is a little better,...

### contourplot of an ode

September 14 2012 by Maple 16

0

1

Is it possible to have a contour plot of an ode,

restart:with(plots);alpha:=1:

de1:=alpha*diff(f(y),y$4)+(diff(f(y),y$2)*diff(f(y),y$3)^2+diff(f(y),y$4)*diff(f(y),y\$2)^2);

with  such type of bcs?

bc1:= f(1+sin(x)) = .95, f(-.1-.1*sin(x)) = -.95, (D(f))(1+sin(x)) = -1, (D(f))(-.1-.1*sin(x)) = -1;

contourplot({de1,bc1}, [x,y, f(y)],x=1..10, y=1..10);

Thanks

### Number of contour lines

April 08 2012 by

0

2

Hi

I want to make a 3D-plot with the style "surfacecontour". My question is: How do I define the number of contourlines? As I understand the default value is 10, but I only want 4.

I hope you can help me!

### How do I obtain the output levels from...

January 17 2012 by Maple 15

0

3

Hi there.

I'm making some 2D contour plots and am desperate to know what the values are which are assigned to the different contour levels. e.g., a red band must be reading value 120 (say) and an orange one 80, but how can I get this and show it on a legend in the plot? It's crucial to the value of the plot.

Many thanks for any help!

David

### why unknown options method = contour?

October 22 2011 by Maple

int(cos(a*z)/(z^2-4*z+8), z, method=contour)

why run in maple 15, unknown options method = contour

is it default to use contour?

but the result is the same as done by hand, i mean the answer from the book,

int(cos(a*z)/(z^2-4*z+8), z) return contain some Si  and Ci

### Any Example can help see the difference...

October 17 2011 by Maple

0

2

Any Example can help see the difference between contour and simple integration?

int(XXXX, x, method = contour);

int (XXX, x)

which example can help to see the difference?

### Drawing the contour of integration

July 22 2011 by Maple

2

2

My contour of integration is a semi circle whose diameter rests on the imaginary axis from -ri to ri.  The arc of radius r is on the positive real axis going from -ri to ri.  On the curve I want to have directional arrows indicating that I am traversing this contour in the positive direction.  How do I create this figure in MAPLE?

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