Mathematica

Surface integral on a 3D region
I have been working on a problem that involves integrating odd shapes, that is, shapes defined by surfaces that are not on constant coordinate planes. The concept of working with regions defined by inequalities is new to me. My shape is a cylinder with one normal and one oblique termination: In[6]:= region = ... 29 Jul 2010 07:29

AxesLabel parallel to 3D axes?
If one sets the AxesLabel option for, for example, Plot3D, is there any way to set things up so that resulting labels are always parallel to their own axes? ....here is an example, and a customer would like the labels to align along/paralle the axes rather than what is shown here.... Plot3D[x y, {x, 0, 1}, {y,... 6 Aug 2010 07:09

Dynamic programming and Manipulate
Hi group, I'm attempting to model a 3-dimensional recurrence relation with two variable parameters a and b as follows: discretemodel[a0_, b0_] := Module[{a = a0, b = b0}, prob[1, 1, 1] = 1.0; prob[1, x_, y_] = 0; prob[t_, 0, y_] = 0; prob[t_, x_, 0] = 0; prob[t_, x_, y_] := prob[t - 1, x - 1, y]*a ... 2 Aug 2010 08:08

How to remove cells with a style?
How to remove all cells with "text" style, i.e. strip all comments from a Mathematica notebook? TIA slawek ... 31 Jul 2010 03:13

modifying standard representation of DiracDelta
Hi, mathematica seems to have the standard representation of the DiracDelta function set to a*DiracDelta[1+b*f] (with a and b being complex values and f being the free variable). At least that is the form I get from using the FourierTransform (for example FourierTransform[Cos[t], t, f, FourierParameters -> {... 28 Jul 2010 03:07

Student's T Confidence Interval [StudentTCI]
I don't understqnd how this function is working. I have a sampe mean of 12, standard deviation of 21, sample size of 10 and level of significance of .05. The t critical value I get from a table for a 2-tail test (p=. 05/2=0.025 and df=10-1=9) is 2.262 My standard error of the estimate is std dev divided by s... 29 Jul 2010 07:29

FindRoot with NDSolve inside of it doesn't work
Hi, I think it's completely self-explanatory what I'm trying to do in this model example: f[x0_, y0_] := ( sol = NDSolve[{x'[t] == x[t], y'[t] == y[t], x[0] == x0, y[0] == y0}, {x, y}, {t, 0, 1}]; {x[1], y[1]} /. sol[[1]] ) (*f[x0_, y0_]:={x0 Exp[1], y0 Exp[1]}; (* Works for this f *) *) ... 29 Jul 2010 07:28

NDSolve for catenary
Hi, This: NDSolve[{ 1 + r'[x]^2 - r[x] r''[x] == 0, r[0] == r[1] == 1}, r, {x, 0, 1}] should solve the catenary problem, but it gives 1/0 errors. Can you suggest a fix? Many thanks! Sam ... 29 Jul 2010 07:29

TeXForm in 7.0.0
Apparently, when there are consecutive TeXform commands on the same cell separated by carriage return, only the last one produces an output. This does not happen with TraditionalForm. I seem to remember that in previous versions of mathematica this was not the case (I am on 7.0.0, Mac version). Is this a known bug? ... 29 Jul 2010 07:29

Wire Frame Surface_Rainbow Colored
Hi: I have the following Mathematica 6.0.1 code: Plot3D[Exp[-x^2 - y^2], {x, -2, 2}, {y, -2, 2}, PlotStyle -> None, Mesh -> 10, MeshStyle -> {Directive[{Thick, Cyan}], Directive[{Thick, Gray}]}, Boxed -> False, Axes -> False] The plot appears as a wire framed surface, with 2 different colors. Question:... 28 Jul 2010 08:31