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15h
comment How to find all roots of a complex number
Can also just use Solve[x^4 == 1 - I, x]
20h
comment Why does my code produce NDSolveValue::ndnum?
It works for me on V10: !Mathematica graphics try rebooting Mathematica to clear things.
23h
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.
23h
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.
23h
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
1d
comment Using conditionals to check if LinearSolve found a solution
can you post an example where LinearSolve[A,b] returns LinearSolve[A,b] and nothing else?
1d
comment DSolve will not apply assumption `m ∈ Integers`
I do not think DSolve uses/accepts user assumptions. This was my understanding all along. Unless something changed in newer version of M.
1d
comment Calculating Value-At-Risk (VaR) in Mathematica. A simple code
what is the question?
2d
comment Derivative of an expression containing a symbolic sum
so there is going to be a term in the series in the denominator where \[Alpha]=\[Beta] This I do not understand at all. You are doing symbolic differentiation? How is Mathematica supposed to know that Alpha and Beta are the same symbol at one point?
2d
comment Derivative of an expression containing a symbolic sum
appears explicitly in the numerator, and implicitly in the denominator due to the sum I do not see it. The denominator has no Subscript[\[Lambda], \[Alpha]] in it at all. The sum is over beta, not alpha. Here is screen shot of your expression !Mathematica graphics
Oct
18
comment Getting a blank plot when plotting two functions with Plot3D
You have a simple mistake. Simply add value for L as in L = 1; and now the plot shows up. You could have seen this easily by evaluating each line of code on its own before the plot command and you would have seen that L is not defined.
Oct
18
comment Getting a blank plot when plotting two functions with Plot3D
Your code is not valid for copying. Try posting it again. Copy the as cell as plain text. For best result, convert the cell to InputForm before. (backup your cell before, just in case). ps. no need to make the title all UPPERCASE, it appears as if you are shouting when doing this.
Oct
12
comment StateResponse is non-deterministic
@Mathxy btw, It might be a good idea to send this to support@wolfram.com.
Oct
12
comment StateResponse is non-deterministic
@Mathxy As I said, I do not know internally what happens. CLearly this is a bug, but you asked for a workaround. There was some changes in v10 with processing of diracdelta's in control system. May be this is related. See mathematica.stackexchange.com/questions/57891/…
Oct
12
comment Why this gives 0?
@Anixx that is correct, that is why I used ExpToTrig to make it generate a result. Ofcourse Exp[t] and ExpToTrig[Exp[t]] are the same thing, mathematically speaking. But one gives a result and one does not. That is why. Just to see the zero come out. Else will not see it.
Oct
12
comment Why this gives 0?
I did not notice the /w. But still, I do not see how it the final result should be Sinh[x]. I think the 0 is not correct and I know why it does it, but I do not see how you came up with Sinh[x] either. But not important. I think 0 is not correct.
Oct
12
comment Why this gives 0?
Can you explain why the result should be sinh(x)? Lets assume all is perfect, and so InverseFourierTransform[FourierTransform[Cosh[t]]] should in theory return back Cosh[t], right? (inverse(fourier(foo))) is foo. Then why is I*Cosh[h]=Sinh[x]? Where did this come from?
Oct
12
comment How to export a text into eps without splitting
it works fine for me. Version 10.01 on windows.
Oct
11
comment How do I find the expression for where the first derivative equals 0?
Mathematica does not have Sqr function. !Mathematica graphics I am using V 10.01
Oct
10
comment Epilog with text not shown
You are telling it to put the text at {-12,10} but you are saying the plot range should be {-10,10} ? So it will not show up. Try Plot[x^2, {x, -13, 10}, Frame -> True, Epilog -> {Text[Style["S", FontFamily -> "Helvetica", Black, Bold, 20], {-12, 10}]}]