Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options answers only not deleted user 121

Questions about the function Assuming[], the $Assumptions system variable, and the Assumptions option of functions such as Simplify[] and Integrate[].

3 votes
Accepted

Display returned integral containing assumptions with integral sign

Something like this: MakeBoxes[ Integrate[a__, Assumptions -> _], fmt : TraditionalForm ] := MakeBoxes[Integrate[a], fmt] Now when you view the integral in TraditionalForm: Integrate[f[x] Sin[( … : Integrate[f[x] Sin[(n π x)/L], {x, 0, L}, Assumptions -> k > 0 && L > 0] // TeXForm \int_0^L f(x) \sin \left(\frac{\pi n x}{L}\right)\, dx …
Mr.Wizard's user avatar
  • 273k
2 votes

How make D[f,x] treat OverBar[x] as a constant

If you prefer not to have to make the replacement each time: OverBar'[x] = 0; f = a*x + OverBar[x] D[f, x] a*x + OverBar[x] a
Mr.Wizard's user avatar
  • 273k
5 votes
Accepted

How do I SetDelayed $Assumptions

A helper function to make this cleaner: SetAttributes[mySet, HoldAll] mySet[LHS_Symbol, RHS_] := (OwnValues[LHS] = {HoldPattern[LHS] :> RHS};) Now: mySet[$Assumptions, Print["y"]; x > 0] (* nothing … prints *) and: Refine[{x < 0, x == 0, x > 0}] y {False, False, True} Also: mySet[$Assumptions, Print["y = ", y]; x > y] y = 1; Refine[{x > 1, x > 2, x > 3}] y = 2; Refine[{x > 1, x > 2, …
Mr.Wizard's user avatar
  • 273k
9 votes
Accepted

Simplifying conditional expressions using assumptions does not work

If you are willing to use Assuming, which acts by way of [$Assumptions](http://reference.wolfram.com/language/ref/$Assumptions.html), you can use an `$Assumptions-aware [Condition](http://reference.wolfram.com … [x ∈ Reals] is evaluated Simplify uses the value of $Assumptions and determines that x ∈ Reals is True The Condition passes and f[x] evaluates to "success!" …
Community's user avatar
  • 1
3 votes

Why does Assuming[...] work in one case but not in another?

Your function must hold its argument or the Simplify will evaluate before the function even sees it. Use: Function[expr, Assuming[α > 0 && ϵ > 0 && t > 0, expr], HoldFirst] Or: SetAttributes[myAs …
Mr.Wizard's user avatar
  • 273k
1 vote

Evaluating an expression assuming a value for a variable only in the local context

While m_goldberg's answer is correct*, provides a proper explanation, and uses only documented behavior, there exists a cleaner syntax for the example given: x = 42.; With[{q := x}, NIntegrate[x^2*q …
Mr.Wizard's user avatar
  • 273k
5 votes
Accepted

How to select TransformationFunctions based on Assumptions made when using Simplify?

Since Simplify is responsive to $Assumptions and by extension Assuming we can use it to check our Condition. …
Mr.Wizard's user avatar
  • 273k
4 votes

Detecting operator Set in Assumptions

Simplify::badSet = "Function Set used in assumptions where is likely in error."; SetAttributes[mySimplify, HoldAll]; mySimplify[expr_, assum_] := Message[Simplify::badSet] /; ! … FreeQ[Unevaluated@assum, Set] mySimplify[else__] := Simplify[else] Now: mySimplify[x + y, x = a] Simplify::badSet: Set used in assumptions where is likely in error. >> You could overload Simplify …
Community's user avatar
  • 1
3 votes

Attaching persistent assumptions to symbol definition

The TransformationFunctions option for Simplify and FullSimplify allows you to create custom simplification manipulations that can be used either in place of or in addition to the defaults. Combined …
Mr.Wizard's user avatar
  • 273k