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Oct
23
comment Problem with series expansion and integrate
@rhermans I only studies Series expansion for functions at school. Teacher never mentioned series expansion for integrals. So I do not know. You could be right. I'll ask the teacher tomorrow when I go to school.
Oct
23
comment Problem with series expansion and integrate
The integration does not even do anything. Why even worry about what Series does? What is Series supposed to be when given an un-evaluated integral anyway? Is this even defined somewhere? Series work on functions.
Oct
23
comment Calculate expected value of piece-wise pdf
Just use Plot. I just typed DiscretePlot cause I was looking at example. Once you have Distribution, you can use Mean on it. As in Mean[D0] gives 3/4 There is also expectation, reference.wolfram.com/language/ref/Expectation.html
Oct
23
comment Calculate expected value of piece-wise pdf
hum.. Should not your function be Piecewise[{{1, 0 < x < 1/2 || 1 < x < 3/2}, {0, True}}] ? Otherwise, looks ok. Try it, like this D0 = ProbabilityDistribution[Piecewise[{ {1, 0 < x < 1/2 || 1 < x < 3/2}, {0, True}}], {x, -Infinity, Infinity}]; then you can plot it. DiscretePlot[Evaluate[CDF[D0, x], {x, -10, 10}]], etc... see help for more information.
Oct
23
comment Calculate expected value of piece-wise pdf
This is a function definition. Not PDF. Check how to define own PDF here reference.wolfram.com/language/ref/ProbabilityDistribution.html
Oct
22
answered Simplifying vector expressions
Oct
22
answered Manipulating array
Oct
22
comment Strange integration
which version are you using? on V10.01, I do not get 1/2 (-HarmonicNumber[-I] - HarmonicNumber[I]), but only Recursion depth. btw, doing NIntegrate[...] works and gives -0.396291 + 1.65436*10^-24 I which is the correct numerical value that you show there. screen shot: !Mathematica graphics
Oct
22
answered Replace list of symbols in an expression
Oct
22
answered Conditional combining of nested lists
Oct
22
revised Partial fraction decomposition of $1/(e^x-1)$
typos
Oct
22
answered Partial fraction decomposition of $1/(e^x-1)$
Oct
22
comment Exclude Infinite Value in Table
It works if you add -1. DeleteCases[{1, {2, Infinity}, 3, {4, 1/0}}, Infinity | ComplexInfinity, -1] gives {1, {2}, 3, {4}}
Oct
22
comment Exclude Infinite Value in Table
Is there any way to tell Mathematica to skip Table values based on some rule? how about DeleteCases ? Example: DeleteCases[{1, 2, Infinity, 3, 4}, Infinity] gives {1, 2, 3, 4} or DeleteCases[{1, 2, Infinity, 3, 4, 1/0}, Infinity | ComplexInfinity]
Oct
22
answered NDSolveValue with a multiple variable equation
Oct
21
comment How to find all roots of a complex number
Can also just use Solve[x^4 == 1 - I, x]
Oct
20
comment Find all roots in range
Does Solve[Zeta[1/2 + I y] == 0 && 0 < Abs@y < 100, y, Complexes] give same result as your method? For numerical, one can always throw N on it with some precision value as needed? I did not compare if this gives same results as what you have.
Oct
20
comment Why doesn't FullSimplify simplify expressions with DiracDelta?
may be because it does not know if x>y? Assuming[x > 0 && y > 0 && x > y, FullSimplify[x/y DiracDelta[x - y]]] gives zero. (I assume you are looking for zero as answer.) The point is, just telling M that x>0 and y>0, does not say anything about if x==y or not.
Oct
20
comment Find all roots in range
Solve works also: Solve[Zeta[1/2 + I y] == 0 && -10 < Abs@y < 10, y, Complexes] gives {{y -> (5 I)/2}, {y -> (9 I)/2}, {y -> (13 I)/2}, {y -> (17 I)/2}} So does NSolve
Oct
20
revised Manipulate showing the trajectory of a particle
added 63 characters in body