Description:
Mathematica discussion group. (Moderated)
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RSolve problem: won't solve convolution recurrence relation.
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I am using mathematica 7, and am trying to solve a recurrence relation using the code below: RSolve[{f[x] == Sum[f[i]*f[x - i], {i, 1, x - 1}], f[1] == 1}, f[x], x] but it gives me the RSolve::piarg error. I have found that the solution for the above problem is in fact f[x_] = Product[(4*i - 6)/i, {i, 2, x}]... more »
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JLink error
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I created a jar file that runs methods that I have created in Mathematica. The java file has everything(libraries, import) it needs to connect to the Mathematica Kernel and run the methods. My issue is that I am using my jar file in Ruby. I have imported the jlink library, my jar file, and everything else I feel it needs to run... more »
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inequality as constraints on NDSolve
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Dear Mathematica experts: is there a possibility to implement a constraint in NDSolve? Suppose I want to solve NDSolve[{x'[t] == -y[t] - x[t]^2, y'[t] == 2 x[t] - y[t]^3, x[0] == y[0] == 1}, {x, y}, {t, 20}] But I want that the solutions satisfied the inequality x[t]>0 for every t (because it represent a physical quantity that has no meaning to be... more »
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"more kernels than you are licensed"
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I am running Mathematica 7.0.1 on Linux (I am more of a Windows guy, but the group I am in only has my darling Mathematica on Linux installations). Now I am receiving the extremely annoying error "The kernel failed to start because you are running more Mathematica kernels than you are licensed". I went to manage the system processes and killed all of those related... more »
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Bind double-[ to keyboard shortcut
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In a previous installation of Mathematica, I had (on a Mac) Command- Alt-8 bound to the character representing double-[ for use in list indexing. I lost this setup in an upgrade and now I cannot create this customization again :-( Anyone know of what I'm talking? Thanks in advance! ..Per
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Four downloaded Workbench installation files corrupted
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Hi, Up to four attempts to download the installation file of the Workbench (for windows v.1.1) rendered four corrupted files, as warned by the installation procedure. I already sent the ticket to the WRI support. Has anyone had this kind of problem before and can provide any help? E. Martin-Serrano... more »
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Combining data from indexed lists efficiently
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I have several lists of the format: { {index1, value}, {index2, value}, ... {indexN, value} } For example: list1 = { {"A", 1}, {"B", 2}, {"C", 3}, {"D", 4} } list2 = { {"A", 5}, {"B", 6}, {"D", 7}, {"E", 8} } list3 = { {"A", 9}, {"B", 10}, {"C", 11} } The indexes are not necessarily strings; they may be any expression. (In... more »
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Wrong ODE solution in Mathematica 7?
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Hi! I tried solve the ODE: DSolve[D[y[x], x, x] == -Cos[x]/(1 + Sin[x])^2, y[x], x] The solution what M7 (and Wolfram Alpha) gives is: y[x] -> C[1] + x C[2] + (2 Sin[x/2])/(Cos[x/2] + Sin[x/2]) I think, it's wrong! (Does anybody know how to check?) Another system gives for the same diff.eq: y(x) = -2/(tan((1/2)*x)+1)+_C1*x+_C2... more »
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