Integrating function with /; in its definitionHow to make InverseFunction work on function defined with...
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Integrating function with /; in its definition
How to make InverseFunction work on function defined with restriction on argumentsIntegrating a periodic functionHow to Integrate trivial products of DiracDeltaIntegrating expressions with several terms and delta functionsSubstitute a function's definition for its nameMathematica `Integrate` evaluates some integrals only with some specific scaling factorPlotting a function involving Nsolve in its definitionDefinition of a periodic function doesn't work when given as the forcing function of an ODEProblem with pendulum code cant get to plot Mathematica 11.3Define Function using another Function and plot
$begingroup$
why
f[x_ /; x>=0]:=x;
Integrate[f[x] ,{x,0,2 Pi}]
return unevaluated? Notice that the above definition of f[x]
works OK with other Mathematica functions, such as Plot
Plot[f[x], {x, 0, 2 Pi}]
While the following works with Integrate
f[x_]:=x;
Integrate[f[x] ,{x,0,2 Pi}]
I am using version 11.3 on windows.
calculus-and-analysis function-construction
$endgroup$
add a comment |
$begingroup$
why
f[x_ /; x>=0]:=x;
Integrate[f[x] ,{x,0,2 Pi}]
return unevaluated? Notice that the above definition of f[x]
works OK with other Mathematica functions, such as Plot
Plot[f[x], {x, 0, 2 Pi}]
While the following works with Integrate
f[x_]:=x;
Integrate[f[x] ,{x,0,2 Pi}]
I am using version 11.3 on windows.
calculus-and-analysis function-construction
$endgroup$
3
$begingroup$
It's better to use ConditionalExpression, e.g.,Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
$endgroup$
– Carl Woll
3 hours ago
add a comment |
$begingroup$
why
f[x_ /; x>=0]:=x;
Integrate[f[x] ,{x,0,2 Pi}]
return unevaluated? Notice that the above definition of f[x]
works OK with other Mathematica functions, such as Plot
Plot[f[x], {x, 0, 2 Pi}]
While the following works with Integrate
f[x_]:=x;
Integrate[f[x] ,{x,0,2 Pi}]
I am using version 11.3 on windows.
calculus-and-analysis function-construction
$endgroup$
why
f[x_ /; x>=0]:=x;
Integrate[f[x] ,{x,0,2 Pi}]
return unevaluated? Notice that the above definition of f[x]
works OK with other Mathematica functions, such as Plot
Plot[f[x], {x, 0, 2 Pi}]
While the following works with Integrate
f[x_]:=x;
Integrate[f[x] ,{x,0,2 Pi}]
I am using version 11.3 on windows.
calculus-and-analysis function-construction
calculus-and-analysis function-construction
edited 15 mins ago
J. M. is computer-less♦
97.3k10303463
97.3k10303463
asked 3 hours ago
NasserNasser
58.1k489206
58.1k489206
3
$begingroup$
It's better to use ConditionalExpression, e.g.,Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
$endgroup$
– Carl Woll
3 hours ago
add a comment |
3
$begingroup$
It's better to use ConditionalExpression, e.g.,Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
$endgroup$
– Carl Woll
3 hours ago
3
3
$begingroup$
It's better to use ConditionalExpression, e.g.,
Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
$endgroup$
– Carl Woll
3 hours ago
$begingroup$
It's better to use ConditionalExpression, e.g.,
Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
$endgroup$
– Carl Woll
3 hours ago
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
f[x_ /; x>=0]:=x
means "if whatever>=0
rewrite f[whatever]
as whatever
. But that doesn't apply to f[x]
when x
is a symbol without a numerical value. Thus, f[x]
simply remains f[x]
. For abstracting the notion of a function with a break like this, use Piecewise
or HeavisideTheta
: Integrate
understands what those mean.
$endgroup$
add a comment |
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1 Answer
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active
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
f[x_ /; x>=0]:=x
means "if whatever>=0
rewrite f[whatever]
as whatever
. But that doesn't apply to f[x]
when x
is a symbol without a numerical value. Thus, f[x]
simply remains f[x]
. For abstracting the notion of a function with a break like this, use Piecewise
or HeavisideTheta
: Integrate
understands what those mean.
$endgroup$
add a comment |
$begingroup$
f[x_ /; x>=0]:=x
means "if whatever>=0
rewrite f[whatever]
as whatever
. But that doesn't apply to f[x]
when x
is a symbol without a numerical value. Thus, f[x]
simply remains f[x]
. For abstracting the notion of a function with a break like this, use Piecewise
or HeavisideTheta
: Integrate
understands what those mean.
$endgroup$
add a comment |
$begingroup$
f[x_ /; x>=0]:=x
means "if whatever>=0
rewrite f[whatever]
as whatever
. But that doesn't apply to f[x]
when x
is a symbol without a numerical value. Thus, f[x]
simply remains f[x]
. For abstracting the notion of a function with a break like this, use Piecewise
or HeavisideTheta
: Integrate
understands what those mean.
$endgroup$
f[x_ /; x>=0]:=x
means "if whatever>=0
rewrite f[whatever]
as whatever
. But that doesn't apply to f[x]
when x
is a symbol without a numerical value. Thus, f[x]
simply remains f[x]
. For abstracting the notion of a function with a break like this, use Piecewise
or HeavisideTheta
: Integrate
understands what those mean.
answered 3 hours ago
John DotyJohn Doty
7,32811124
7,32811124
add a comment |
add a comment |
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3
$begingroup$
It's better to use ConditionalExpression, e.g.,
Integrate[ConditionalExpression[x, x>0], {x, 0, 2Pi}]
$endgroup$
– Carl Woll
3 hours ago