# Questions tagged [assumptions]

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### Assumptions allowing to calculate an elliptic integral

When I feed Mathematica the following integral: Integrate[Sqrt[(A - x) (B - x)/x], {x, 0, B}] it spits it back out without evaluating it. However, it can ...
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### Problem with DiracDelta evaluating to zero

I am having an issue (in Mathematica 11.2.0.0) where the following integral evaluates to zero: ...
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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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### How to state nontrivial tensor symmetry assumptions?

For example dddg, the third derivative of the metric tensor, in dimension $4$. I need to state that it is symmetric in the first two indices and symmetric in the ...
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### Logarithm of exponential [closed]

Ok, this is awkward. E^Log[a] gives a, which is what I expected, BUT, Log[E^a] is not ...
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### Getting long complex-valued integrals when simpler real-valued expressions exist

I have a long list of real-valued functions I'd like to integrate symbolically. For many of them, Mathematica gives me results with long complex-valued expressions involving weird functions such as <...
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### Assumptions in Integrate not working properly

I have the following code: ...
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### Assumptions behavior in Refine[Sin[n Pi/2]] [duplicate]

I don't understand why this first expression returns a correct result: In> Refine[Sin[n Pi/2], Element[n, Integers] && Mod[n, 2] == 1] ...
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### Why does restricting the domain not eliminate this solution?

Beside this specific problem I'm wondering if there's a more explicit way that I can understand when Solve and Reduce will find solutions. I find myself repeatedly getting stuck where I'll get ...
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### How to best add assumption that many variables are positive?

I often need to check whether integrals are solvable in closed form and use a notebook with 5–10 variables that need to be assumed positive. Is there a better way of doing this than adding the clunky ...
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### Simplification of symbolic vector and matrices representation

I'm new to the Wolfram Language programming and I cannot manage to do the following. I wish to use Wolfram Cloud to simpilfy a heavy vector and matrix expression using symbolic complex vectors (...
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### I need to create abstract vectors

$Assumptions = {q \[Element] Vectors[{15}, Reals]};$Assumptions = {p1[q] \[Element] Vectors[{3}, Reals]}; So I have been using this code in order to define an ...
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### Count based hypothesis test for inhomogeneous Poisson process

I am intended to fit the following data using InhomogeneousPoissonProcess[] in v12.0. The original form of data tabulated given as below Such a table contains ...
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### Mathematica assumptions [closed]

Mathematica produces the answer to integral((x + 5)/(x^2 + x − 2) dx). Find what is missing and explain what assumptions it seems that Mathematica is making.
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### Why does this boolean computation get stuck?

I want to build a boolean function which takes three one-parametric functions. I really don't know how to write a function for this, but this seems to be working for me as long as the parameter is <...
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### Does Assumptions not work on Root objects?

Typically, one can restrict symbolic quantities using Assumptions. Suppose, for instance, that I want to solve $a=x^2$ for $x$, with $a>0$, restricting my answer to the positive root. ...
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### Is my expression too complicated for FullSimplify or am I doing something wrong?

I have a messily defined function $v(h, w)$ with $h, w \in \mathbb{R}$ and with a removable singularity at $h=1/2$, and I am trying to prove some of its properties using Mathematica. In particular I ...
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### Getting around symbol favoritism of Simplify and FullSimplify [duplicate]

Simplify may or may not simplify depending on the symbols you use for its assumptions are good. For example, here is a case where ...
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### How do I apply assumptions to a table of functions

I have a table, really its a tensor but anyways I would like to apply an assumption to it, i.e. 1 - 2 phi[t,x,y,z] == 1 and have it print the tensor after it has ...
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### Simplifying square roots of squared reals

I am using Mathematica to check some long, tedious calculations and I am stumped by some mysterious behavior. If I simplify a long expression that clearly has square real factors under a radical, for ...
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### Is it better to use a single binary operator in each Assumption entry?

I am trying to understand why FullSimplify[x^a < 1, {0 < x^a < 1}] does not simplify but ...
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### Display returned integral containing assumptions with integral sign

From solving the PDE example of the general 1 dim heat equation in Nasser Abbasi's site https://www.12000.org/my_notes/pde_in_CAS/maple_2019_and_mma_12/insu157.htm#x182-1810003.1.1 (his problem No 151)...
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### How Simplify and Assume can be combined on matrix products?

What I am trying to do is to simplify some expressions involving matrices! The problem is that Simplify[] considers the simplifications based on alphabetical order and everything is Commutative. For ...
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### Is it possible to use an assumption that a parameter is an odd or even number?

I am trying to integrate: Integrate[(Exp[x]*(x^m)/((Exp[x] + 1)^2)), {x, -Infinity, Infinity}] I know that for odd m the result is zero. How can I tell ...
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### How to apply assumptions to pattern matching?

I'm trying to remove terms whose exponents are positive in a polynomial. I tried this one; Assuming[t > 0, x^t /. {x^a_ /; Positive@a -> 0}] but the result ...
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### Assuming a variable is imaginary

I am confused how to assume a variable is pure imaginary. As a test example, I used the code Assuming[{ x \[Element] I Reals}, Simplify[x + Conjugate[x]]] In ...
I have a Piecewise function, of the type: $Assumptions = b > a > 0 fun[k_] := Piecewise[{{3k, 0<=k<a}, {k^2, a<=k<=b}}] fun[a] When evaluating ... 1answer 53 views ### Is there a global parameter that limits the number of variables handled by Simplify? It seems that Simplify is unable to handle (at least some) expressions involving 22 or more variables. Consider the code snippet below: ... 1answer 143 views ### Simplify is not simplifying a compound inequality as expected The Simplify command is having trouble verifying a compound inequality, even while it correctly handles the two corresponding single inequalities. I'm starting ... 2answers 60 views ### how to get rid of the denominator in the squareroot, that appears in the denominator? Here is an example:$\frac{\nu y_0}{\left(x_0+\frac{1}{2}\right) \sqrt{\nu ^2+\frac{\left(4 x_0^2+4 y_0^2-1\right){}^2}{16 y_0^2}}}$... 2answers 91 views ### Result with assumptions contradicts previous result Without assuming anything on the argument of the complex number inside the Gamma function ... 1answer 44 views ### Exits and beeps on Integration Evaluating ... 0answers 42 views ### Why does Mathematica miss some solutions for my integral? When computing the integral of two orthogonal sine functions$\qquad \sin(n\,\pi\,x)\,\sin(m\,\pi\,x)$, where$n,\,m$are integers > 0 Mathematica seems to miss the solution where$n=m$. I don't ... 0answers 254 views ### What is a “generic case”? Introduction With this question I am coming back to a long-standing issue I have with Mma's concept of a "generically correct" result. The basic idea seems to be, vaguely, that if a result is true in ... 0answers 31 views ### Using assumptions in DSolve I want to solve the following differential equation DSolve[u'[\[Xi]] == a u[\[Xi]]^(2 - m) + b u[\[Xi]] + c u[\[Xi]]^m, u[\[Xi]], \[Xi]] with the assumpetion ... 1answer 83 views ### Domain specifications for InverseFunction I have difficulty implementing on how to specify the domain that I want for ry which is the inverse function of rho. The necessary condition is that,$\textbf{ry}$must remain$\textbf{positive}$for ... 4answers 325 views ### Simplify makes Mathematica forget that a matrix is Hermitian Using Simplify with certain trivial assumptions makes Mathematica forget that a given matrix is Hermitian. See the minimal example below: ... 0answers 53 views ### Dealing with positive power variables in Taylor expansion and assumptions I would like to compute the Taylor expansion of monomials whose powers are nonnegative rational variables. First, here is a function which encodes the multivariate Taylor expansion at the points <... 1answer 60 views ### Using Assumptions [closed] I’m trying to use Assumptions for the set of variables in a form:$Assumptions = {(k, z) ∈ Reals, (k, z) > 0}; But as a result a receive an errors. What is ...
As part of an equation of state calculator that I am working on, I have to handle a virial expansion for the equation of state. As such I have to solve for the virial coefficent, $B(T)$, which is ...