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 1d reviewed Approve How to draw normal vector in Mathematica? 1d reviewed Approve Complex boundary conditions and NDEigensystem Nov 22 comment Determining the largest exponent @john , you are asking people to make an effort to help in solving your problem. You could at least make the effort of copying and pasting a snippet of the code you already have, don't you think? It's hard to tell if you are having problem with Exponent (reference.wolfram.com/language/ref/Exponent.html), Coefficient, CoefficientList, Product (like in changing the Product into a Sum before calling Exponent), the act of extracting the polynomial, avoiding the overarching evaluator or just the syntax. Nov 22 comment Determining the largest exponent Code, or it does not happen! Nov 22 awarded Nice Answer Nov 22 comment Is Mathematica worth it for me? @OleksandrR. I see your point. The ancient Romans used to train with weapons much heavier than those used in battle. My advice is: avoid MMA as long as possible during training (when learning), but when in battle (when applying what you learned - more so when working) take the most advantage you can from that powerful tool. From 13 to 18-21 I believe one should stress the brain the most one can. After that, it's too late to learn certain tricks (but luckily one can still rely on MMA! :-) ) Nov 22 revised Is Mathematica worth it for me? Syntax, Semantics, Overall meaning. Nov 22 comment Is Mathematica worth it for me? As a non-native speaker, I must have underestimated the meaning of "bashing" ("to break one's head on a problem" is what I had in mind). Perhaps a simple "banging" is better suited when communicating with a 13 yr old. :-). I like to think at ideas as tetris pieces: at some point in the study of a subject one ends up with a messed-up configuration where there seems to be no hope. But with a bit of figurative banging against a wall, the pieces can manage to arrange themselves in the perfect configuration. That's what I call satori. (Kid, please do not smash your head physically against a wall!) Nov 21 answered Is Mathematica worth it for me? Nov 10 awarded Good Question Nov 9 reviewed Approve discrete Fourier transform Oct 26 comment How to transform data in character form into a sensible form? Have you tried something along the lines of ReadList["filename", Number, WordSeparators -> {" "}, RecordLists -> True, RecordSeparators -> {"\n"}] on the file "filename" whose content is StringJoin[lst]? ReadList can manage multiple trailing spaces and Fortran-like E notation. Oct 26 awarded Civic Duty Oct 23 comment How to tell Mathematica that an expression is constant w.r.t a variable? Also have a look at my answer here: mathematica.stackexchange.com/questions/38166/… ; the role of linearity is explicit. Oct 22 comment How to tell Mathematica that an expression is constant w.r.t a variable? That piece of code instructs mathematica to take r out of the integral if it is "Free of v's", i.e. if it does not contain terms with the variable v. The triple underscore means zero, one or more terms; the double underscore means one or more terms. So the pattern q1___ r__ q2____ means "that r or rs that can be at the beginning, in the middle or at the end of an expression". And you repeatedly apply the substitution rule by means of ReplaceRepeated, whose shot form is //. Oct 14 comment How do I solve for a variable inside a sum but independent of the summation index? For simple problems such as yours, you might try Summa.m, you need to patch it for use with the latest versions of mma, as shown here mathematica.stackexchange.com/questions/31426/… . Please note, you won't be able to use solve directly, but you might find the simplification and BringOut functions useful. (Usage and help are available on the Mathsource). Oct 4 comment Find the volume of Phobos and Deimos Off the top of my head: slice the solid surface into intersection with parallel planes and then use one of those "is point inside a 2D polygon" test to see if it's inside. (@Szabolcs - you could not have seen my comment, so your question is more than justified). An even easier way: 3Dprint the darn satellites and put them into water to measure the displaced volume :-) Oct 4 comment Find the volume of Phobos and Deimos My comment (which I deleted before hitting enter and writing this) was "IF you can find an efficient test to tell if a point is inside or outside the shape, you could try a Montecarlo method: generate random points in a cube containing your shape e see what fraction of them is inside the volume." (emphasis added now) :-) Oct 4 comment Find the volume of Phobos and Deimos I was going to suggest a Montecarlo method, but then I saw you want to use computational geometry procedures... Sep 29 reviewed Approve How can I use Mathematica to solve a Stefan Problem using an explicit scheme?