Mathematica

A simpl(e)ification
Dear All, With Mathematica 7.0.1, the following expression; Simplify[ Im[E^(-2 I a) b], Assumptions -> Element[a, Reals] && Element[b, Reals]] gives -b Sin[2 a] But: Simplify[ Im[E^(-2 I a) 1/b], Assumptions -> Element[a, Reals] && Element[b, Reals]] gives Im[E^(-2 I a)/b] So we see tha... 19 Dec 2009 07:17

Cannot solve very simple equation.
NSolve[x^2 + 1 == 2^x] "Solve::tdep: "\!\(\* StyleBox[\"\\\"The equations appear to involve the variables to be solved for in an essentially non-algebraic way.\\\"\", \"MT\"]\) "" Am I forgetting something trivial here? ... 20 Dec 2009 07:04

Help needed using NDSolve and NIntegrate
Hello, I have a system of differential equations I am trying to solve numerically. On the right-hand side of the ODEs I must numerically integrate a quantity which is spatially distributed. I tried a simple and direct approach of using NIntegrate[] on the RHS, but I am getting warning messages and I think there ... 17 Dec 2009 08:10

Repeat Data reading in one file
Hello I am posting my question.. The question is I have multiple files with following data structure.. Header..1 Header..2 1 3.12 2. 2.54 .. .. .. Header...2 1. 1.24 2. 5.44 .. .. .. .. Header...2 1. 1.24 2. 5.44 .. .. .. .. I tried to take out only the number in each data set. ... 19 Dec 2009 07:17

ParallelTable slows down computation
Hi, I was trying to evaluate definite integrals of different product combinations of trigonometric functions like so: ClearSystemCache[]; AbsoluteTiming[ Table[Integrate[ Sin[ph]*1/(2 Pi)*Sin[nn*ph]*Cos[mm*ph], {ph, Pi/2, Pi}], {nn, 0, 15}, {mm, 0, 15}];] I included ClearSystemCache[] to get ... 17 Dec 2009 08:10

Any way to make "iterb" in Mathematica 7.0 compatible with older
Hi, I was wondering if anyone here knows of a way to force 7.0 to behave like 3.x in the way it works with iterb in Table and Do. I'm currently trying to run grtensorm (grtensorii for Mathematica) from http://grtensor.phy.queensu.ca/software.html and am getting iterb errors left and right. A relatively benign ... 15 Dec 2009 07:51

Free online Mathematica seminars in December
Wolfram Research runs free online seminars on varied topics, ranging from beginning to advanced. Each seminar runs about 60 minutes and usually allows time for live Q&A with technical staff. Mathematica seminar catalog: http://www.wolfram.com/services/education/seminars S27: Got Manipulate?--December 15, 10am ... 15 Dec 2009 07:51

Buying and running older version of Mathematica on a Netbook
Hello: Is it possible to buy a new copy of Mathematica 5.2 and run it on a Netbook: Acer Single Atom processor, 1 GB Memory, 160GB HD. I am not going to be doing any serious number crunching. I have been searching all over the internet, but don't find any older versions of Mathematica for sale. TIA, ... 17 Dec 2009 08:10

PolarPlot[Log[\[Theta]], {\[Theta], 0.27, 1.7 Pi}]
PolarPlot[Log[\[Theta]], {\[Theta], 0.27, 1.8 Pi}] You will get a curve liking "e" ! Natural const e knows to draw her figure. Beauty comes from spirit! ... 13 Dec 2009 05:38

When to use Hermitian operator?
Dear readers, I have this matrix equation c = T^*f where T^ is the Hermitan operator, and * denotes the complex conjugate. Can someone explain what T^*f does, and why it is needed in this case? Hugs, Louise ... 14 Dec 2009 00:09