Michael Wijaya
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 Jun 14 revised How to substitute numeric values in a symbolic Jacobian matrix? I forgot to define variableVector Jun 14 revised How to substitute numeric values in a symbolic Jacobian matrix? added 192 characters in body Jun 14 revised How to substitute numeric values in a symbolic Jacobian matrix? Stylistic changes, added method to generate vector of variables symbolically Jun 14 answered How to substitute numeric values in a symbolic Jacobian matrix? Jun 14 awarded Civic Duty Jun 13 comment Interprocedural optimization It is possible to compute PrimePi[n] without enumerating all prime numbers less than $n$. See for example Lehmer's recursive formula. Jun 13 revised How do you check if there are any equal arguments(even sublist) in a list? Changed the name of the second function since it is no longer a Boolean function. Jun 13 revised How do you check if there are any equal arguments(even sublist) in a list? Include modifiication to keep track of repeated elements as per OP's request Jun 13 answered How do you check if there are any equal arguments(even sublist) in a list? Jun 13 comment Checking if the roots of a function are real You can try checking that the imaginary part is zero. We can get the list of roots using x /. {ToRules[Reduce[LegendreP[6, x] == 0, x]]}. Then we map Im to each root using Map[Im,%], which gives {0,0,0,0,0,0}. This seems to suggest that the roots are real, but I am not 100% sure. Jun 13 comment Splitting a list @BrettChampion At one point I made a list of things I liked about Mathematica, and it included the fact that everything is an expression. Lisp popped up when I researched the roots of this feature. On a related note, that book really did teach me to write recursions! (Always ask null?, etc.) Jun 13 answered Splitting a list Jun 12 awarded Nice Question Jun 10 revised Implementing Central Symmetry Chose a better reference, more accurate definition of orthogonal group Jun 10 comment Wagner's trick to monitor FindRoot no longer works in Mathematica version 8 @AlexeyPopkov Thanks! Could you also include a link to the documentation where that "standard" trick is explained? I apologize for making so many requests of you. Jun 9 accepted Wagner's trick to monitor FindRoot no longer works in Mathematica version 8 Jun 9 comment Implementing Central Symmetry Szabolcs' image uploader came in handy. Jun 9 answered Implementing Central Symmetry Jun 9 comment Wagner's trick to monitor FindRoot no longer works in Mathematica version 8 @AlbertRetey I am not sure I understand how that trick works in this context. Could you post an answer based on that? Jun 9 comment Can a function be made to accept a variable amount of inputs? +1 Your method is much cleaner than mine. It is good to know about Check too.