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 1d comment Inequality involving Quantity stays unevaluated Simplify also works. Apr22 comment Multiply out product of sums is NN known, or does it need to remain as NN? Mar20 comment Turning a list of notes and timings into useful sheet music You have 10 notes in your song, but 11 entries in your timing list. Should I think of this as: wait 1/4 d5 wait 1/4 d5 wait 1/4 e5 wait 1/4 ... a4 wait 1/2 c5 wait 1/2? Mar5 comment Find the volume & weight of a US\$4,000,000 gold ingot @kirma USA! USA! USA! Mar5 comment Please help translate regular expression to StringExpression @Jeremy As Fred says, a~~b~~c is really StringExpression[a, b, c]. Feb26 comment Ghost trails with Animate? possible duplicate of Creating ghost trail effects Feb25 comment Why does Solve give a wrong solution to an equation? You can also try the option MaxExtraConditions -> 1 Jan29 comment Trouble using Manipulate and NDsolve for coupled ODE's I should note (for clarity) that the proper syntax for Manipulate is: Manipulate[expr, 'controls'], where 'controls' can take various forms (like lists, Control[XXX], etc...). Arguments in WL are separated by commas, and the first argument to Manipulate is the expression to be manipulated. The problem in the OP was that the first argument was actually NDSolve[XXX] and not the CompoundExpression they actually wanted. Jan29 comment How to prevent tiny complex errors in Integrate? Not addressing why you see this particular behavior, but if you want an exact analytic answer, you need exact inputs. 6.5 is not an exact number. Dec18 comment Module function corrupts string? Unless an explicit Return is used, the value returned by For is Null. Dec18 comment Module function corrupts string? it is not a hack to use proper syntax Nov25 comment What quantity is this “length” called? Perhaps you really want a test for the result being a List or not? Then you might look at ListQ (undocumented tho). Nov7 comment Selection bugs make Mathematica 10 unusable support.wolfram.com/kb/12464 Oct2 comment Replacing columns of a matrix with zeros I suppose you could do something like this then MapAt[#*0&,list1,{All,1;;3}] Oct1 comment Outputting numbers symbolically Inactivate[Table[2^n, {n, 1, 5}], Power] (I am not obsessed with Inactive I promise) Oct1 comment Strange style conversion indicator appeared when type “a Pre” From reference.wolfram.com/language/ref/CodeAssistOptions.html it looks like the option is "AutoConvertEnable". Oct1 comment How to regress negative log? Something like NonlinearModelFit[data, -p2 Log[p1 x],{p1,p2},x] where p1 and p2 are parameters? Oct1 comment Spherical parametric plot If you have version 9+ you can use: ParametricPlot3D[Evaluate[CoordinateTransform[ "Spherical" -> "Cartesian",{2 Cos[t]+Sin[t],t,Sin[10 t]}]],{t,0,Pi/2}] Oct1 comment How to simplify symbolic matrix multiplication using the associativity of scalar multiplication? This may be too specific: Thread[(2 A).(3 B), Times] /. Dot[a_?NumericQ, b_?NumericQ] :> a b Sep12 comment Join decimal part just beat me to it, yours is the same as mine (essentially):toDecimal[a_, b_] := N[a + (-1)^Sign[a] b 10^(-IntegerLength[b])]; list /. {a_, b_, c_, d_} :> {toDecimal[a, b], toDecimal[c, d]} (* {0.1, -2.259} *)