# Tagged Questions

Questions about the function Assuming[], the $Assumptions system variable, and the Assumptions option of functions such as Simplify[] and Integrate[]. 1answer 101 views ### How do I apply assumptions to a module (or any CompoundExpression)? Edit: I am looking for a way to apply assumptions to all expressions contained in a compound expression. For example, ... 2answers 94 views ### Verifying inequality in Mathematica I am trying to verify the following inequality Mathematica. This I wrote the fillowing code: ... 1answer 47 views ### DSolve with coefficients and assumptions The command below: DSolve[{s'[t] == l t, s[0] == 0}, {s[t]}, {t, 0, a}] gives the error DSolve::alliv: The function <... 1answer 45 views ### Do double vertical bars in ConditionalExpression mean 'or'? [closed] I have a very simple interpretation question. I think that double vertical bars in a ConditionalExpression given by Mathematica as the result of an integration must mean 'or', but I am hoping to ... 1answer 60 views ### How to assume all variables in my code are reals I won't have any occasion to have any imaginary number in my code. If there are any, that is an error. So allowing the imaginary case simply hinders the equation manipulation and simplification. I ... 0answers 79 views ### Why isn't Mathematica listening to my assumptions? I'm trying to simplify the expression ωplus := 1/2 c (I f V + Sqrt[4 k^2 - f (f + 8 I k) V^2]) so that I can get it in the form$a+i b$. I am using the global ... 1answer 105 views ### Adding irrelevant assumptions changes the result of Simplify I've run into this problem a number of times. A typical example is Simplify[Sign[k], {0 < A, 0 < B, A*Exp[2*y] < k, y > 1}] which evaluates to$1$, ... 1answer 68 views ### How to integrate with integer parameter in Mathematica? I would like to integrate the following expression with N being Integer ... 1answer 68 views ### Eigensystem with orthogonal elements in matrix I have a matrix with 16 elements: matrix = {{f1, -f2, -f2, f3 }, {f4, -f1, -f1, f2}, {f4, -f1, -f1, f2}, {f5, -f4, -f4, f1}} I would like to calculate ... 2answers 70 views ### How do I SetDelayed$Assumptions

For some reason, $Assumptions := (Print["y"]; x > 0) evaluates the RHS immediately. I have code in which$Assumptions ...
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### Assumptions with Multiple Rules

What is the correct way to add more than one assumption while integrating? I am attempting to evaluate the following integral and Mathematica is just stalling, so I'm wondering if my assumptions are ...
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I would like to assume that $x$ is small so that values of the order $x^2$ (and higher orders) are negligible. For example, I would like Mathematica to return $1-2m$ when I ask it to simplify $(1-x)^... 0answers 31 views ### Using assumptions with Integrate [duplicate] I open Mathematica and execute this code: ... 0answers 45 views ### Impose conditions on differential equations This is my first post in Mathematica Stack Exchange, so thanks for your help and sorry for any rookie mistakes. I am solving the Einstein equations for two vectorial pertubations h_Alpha and v_Alpha ... 1answer 37 views ### How to specify assumptions without typing out functions So I want to add assumptions in carrying out integration. I know I could use the Integrate function: Integrate[V Exp[-x/a] ,{x,0,10}, Assumptions->a>0] but ... 0answers 61 views ### Assumptions aren't working in this sum I have a sum that should be real: FullSimplify@Sum[1/(α n^4 + β), {n, 1, ∞}, Assumptions -> α > 0 && β > 0] But the result have involved even ... 3answers 247 views ### Assumptions for RotationMatrix I'm making C++ program, and in my program I need a rotation matrix around any vector. I wanted to extract RotationMatrix[fi,{x,y,z}] output and put it in my program.... 0answers 61 views ### Limit not evaluated [closed] I hope this question ha not been asked since the limit is evaluated in 1 not at 0 or infinity. I do not know how to ask Mathematica to find the limit as n -> 1 of the following function: ... 0answers 30 views ### Finding parameters that give constrained eigenvalues of matrix I want to obtain the eigenvalues$x_1,x_2,x_3$of a hermitian, off-diagonal matrix, {{0, Conjugate[d], Conjugate[g]}, {d, 0, Conjugate[h]}, {g, h, 0}}, under the ... 2answers 73 views ### Minimization of a function with non-numeric parameters? I have the following problem (in Mathematica) I want to calculate the following expressions: ... 0answers 83 views ### Need explanation on strange behavior of Simplify under given assumption This is quite surprising to me. Simplify[a == b, {a == {1}, b == {1}}] a == b does not evaluate the equality, while <... 1answer 88 views ### Getting wrong result when Integrating under an assumption [duplicate] The simple integral $$\int_0^b \cos\left(\frac{2\pi m(y-\eta)}{b}\right) \cos\left(\frac{2\pi \eta}{b}\right)\mathrm{d}\eta$$ can be easily evaluated by Mathematica as, ... 1answer 112 views ### Understanding the symbolic solutions of a system of differential equations I'm trying to solve a simple system of differential equations but get outputs i just cant grasp, they seem way overkill. Someone said it might be because mathematica interprits the constants as non-... 1answer 72 views ### The assumption in integration does not work? I am new to mathematica. Here is the question. I try to do the following integration with the assumption that k1<0, k2<0 and k1,k2 are real number. However, the result includes \sqrt{k1}? ... 1answer 59 views ### Same integral gives different results with assumption b = 1 k = 12560 r = 500 res = Integrate[Exp[I*k*x*Sin[o]]/(r + x*Sin[o]), {x, -b/2, b/2}] resab = Abs[res]^2 Plot[resab, {o, -Pi/20, Pi/20}, PlotRange -> Full] ... 1answer 46 views ### Restrict list to reals for statistics I get conjugates in output when running this: Clear[X]; X:={x1,x2,x3}; Assuming[{Element[X, Reals]},StandardDeviation[X]] What is wrong with the code? 1answer 43 views ### Simplify With Assumptions Not Using Distributive Property Of Dot Product Given the following expression Assuming[(n | d | t) ∈ Vectors[3, Reals] && n.t == 0, FullSimplify[(n + d).t]] Why does mathematica give me the below ... 1answer 89 views ### How to make Simplify (and FullSimplify) give a default output if$Assumptions are contradictory

I have a function (deep inside my package) that looks like ...
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### Problem with Identifying Complex Components

I am trying to isolate out the real and complex terms in a fairly large expression. During the process, I have made several assumptions that last throughout the entire process. ...
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### Assumption that a parameter is real [duplicate]

I'm making some calculations, where I use the command Conjugate[f[x]]. In the function f[x] appears a parameter J, which is Real. How can say mathematica that it should not take the Conjugate of J? ...
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### How to make Maximize function successfully maximize in general?

Having looked at Maximize Documentation SO: Mathematica: Commands return no output, but itself. Bug? Problem with Maximize Why won't Mathematica Solve a set of two equations for one variable? ...
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### Limit of sequence of functions behaving strange

I'm trying to determine the limit of the sequence of functions $$f_n(x)=\left(\frac{1}{\pi}\arctan(n x) + 1/2\right)^n.$$ I define ...
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### evaluation of the sum of KroneckerDelta

I need help. I need to know why the next code doesn't simplify in Mathematica 10 but it does in Mathematica 8. I need some similar in version 10. What can I do? ...
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### Puzzled by Assumptions [duplicate]

I don't know if this has already been discussed. Integrate[BesselJ[2 m + 1, x], {x, 0, ∞}, Assumptions -> m ϵ Integers] ...
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### Usage of Assuming for Integration

For some reason, when I enter the following integration in Mathematica Assuming[{k ∈ Integers}, Integrate[ Exp[ I k t], {t, -π, π}]] the result turns out to be 0....
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### External and internal Assumptions on PiecewiseExpand and Mod

After this question I'm intrigued about the different behaviors depending where and how the assumptions are given. ...
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