How can I solve the limit by mathematica?
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up vote
3
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favorite
I use the Limit
and DiscreteLimit
to solve it but failed. How to solve it by Mathematica?
$$undersetnto infty textlimn left(int_0^fracpi 4 tan ^nleft(fracxnright) , dxright)^1/n$$
calculus-and-analysis
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King.Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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up vote
3
down vote
favorite
I use the Limit
and DiscreteLimit
to solve it but failed. How to solve it by Mathematica?
$$undersetnto infty textlimn left(int_0^fracpi 4 tan ^nleft(fracxnright) , dxright)^1/n$$
calculus-and-analysis
New contributor
King.Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
If you tryIntegrate[Tan[x/n]^n, x, 0, Pi/4]
MMA evaluates a ConditionalExpression which constrains0<n<1/2
. Might be the limit doesn't exist?
– Ulrich Neumann
2 days ago
1
@UlrichNeumann I'm quite sure, it does exist. Atn->Infinity
we can probably replaceTan[x/n]
withx/n
, then the limit is solvable and givesPi/4
– LLlAMnYP
2 days ago
@LLlAMnYP The limit would be1/4 [Pi]^((4 + [Pi])/[Pi]) (4 + [Pi])^(-4/[Pi])
(not Pi/4). I only tried to indicate, that MMA can't integrate ifn>1/2
– Ulrich Neumann
2 days ago
1
@King.Max as you found, as it is Mathematica doesn't solve the limit. It needs some help (i.e. manual interference from the user). If my suggestion isn't acceptable to you, what kind of help would be acceptable? Maybe one could pass some options toLimit
or toIntegrate
, but I can't say for sure.
– LLlAMnYP
2 days ago
1
Try:Limit[n*Integrate[Tan[x/n]^n, x, 0, Pi/4, Assumptions -> n > 1]^(1/n) // PowerExpand, n -> Infinity]
– Mariusz Iwaniuk
2 days ago
 |Â
show 2 more comments
up vote
3
down vote
favorite
up vote
3
down vote
favorite
I use the Limit
and DiscreteLimit
to solve it but failed. How to solve it by Mathematica?
$$undersetnto infty textlimn left(int_0^fracpi 4 tan ^nleft(fracxnright) , dxright)^1/n$$
calculus-and-analysis
New contributor
King.Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I use the Limit
and DiscreteLimit
to solve it but failed. How to solve it by Mathematica?
$$undersetnto infty textlimn left(int_0^fracpi 4 tan ^nleft(fracxnright) , dxright)^1/n$$
calculus-and-analysis
calculus-and-analysis
New contributor
King.Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
King.Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
King.Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 days ago
King.Max
161
161
New contributor
King.Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
King.Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
King.Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
If you tryIntegrate[Tan[x/n]^n, x, 0, Pi/4]
MMA evaluates a ConditionalExpression which constrains0<n<1/2
. Might be the limit doesn't exist?
– Ulrich Neumann
2 days ago
1
@UlrichNeumann I'm quite sure, it does exist. Atn->Infinity
we can probably replaceTan[x/n]
withx/n
, then the limit is solvable and givesPi/4
– LLlAMnYP
2 days ago
@LLlAMnYP The limit would be1/4 [Pi]^((4 + [Pi])/[Pi]) (4 + [Pi])^(-4/[Pi])
(not Pi/4). I only tried to indicate, that MMA can't integrate ifn>1/2
– Ulrich Neumann
2 days ago
1
@King.Max as you found, as it is Mathematica doesn't solve the limit. It needs some help (i.e. manual interference from the user). If my suggestion isn't acceptable to you, what kind of help would be acceptable? Maybe one could pass some options toLimit
or toIntegrate
, but I can't say for sure.
– LLlAMnYP
2 days ago
1
Try:Limit[n*Integrate[Tan[x/n]^n, x, 0, Pi/4, Assumptions -> n > 1]^(1/n) // PowerExpand, n -> Infinity]
– Mariusz Iwaniuk
2 days ago
 |Â
show 2 more comments
If you tryIntegrate[Tan[x/n]^n, x, 0, Pi/4]
MMA evaluates a ConditionalExpression which constrains0<n<1/2
. Might be the limit doesn't exist?
– Ulrich Neumann
2 days ago
1
@UlrichNeumann I'm quite sure, it does exist. Atn->Infinity
we can probably replaceTan[x/n]
withx/n
, then the limit is solvable and givesPi/4
– LLlAMnYP
2 days ago
@LLlAMnYP The limit would be1/4 [Pi]^((4 + [Pi])/[Pi]) (4 + [Pi])^(-4/[Pi])
(not Pi/4). I only tried to indicate, that MMA can't integrate ifn>1/2
– Ulrich Neumann
2 days ago
1
@King.Max as you found, as it is Mathematica doesn't solve the limit. It needs some help (i.e. manual interference from the user). If my suggestion isn't acceptable to you, what kind of help would be acceptable? Maybe one could pass some options toLimit
or toIntegrate
, but I can't say for sure.
– LLlAMnYP
2 days ago
1
Try:Limit[n*Integrate[Tan[x/n]^n, x, 0, Pi/4, Assumptions -> n > 1]^(1/n) // PowerExpand, n -> Infinity]
– Mariusz Iwaniuk
2 days ago
If you try
Integrate[Tan[x/n]^n, x, 0, Pi/4]
MMA evaluates a ConditionalExpression which constrains 0<n<1/2
. Might be the limit doesn't exist?– Ulrich Neumann
2 days ago
If you try
Integrate[Tan[x/n]^n, x, 0, Pi/4]
MMA evaluates a ConditionalExpression which constrains 0<n<1/2
. Might be the limit doesn't exist?– Ulrich Neumann
2 days ago
1
1
@UlrichNeumann I'm quite sure, it does exist. At
n->Infinity
we can probably replace Tan[x/n]
with x/n
, then the limit is solvable and gives Pi/4
– LLlAMnYP
2 days ago
@UlrichNeumann I'm quite sure, it does exist. At
n->Infinity
we can probably replace Tan[x/n]
with x/n
, then the limit is solvable and gives Pi/4
– LLlAMnYP
2 days ago
@LLlAMnYP The limit would be
1/4 [Pi]^((4 + [Pi])/[Pi]) (4 + [Pi])^(-4/[Pi])
(not Pi/4). I only tried to indicate, that MMA can't integrate if n>1/2
– Ulrich Neumann
2 days ago
@LLlAMnYP The limit would be
1/4 [Pi]^((4 + [Pi])/[Pi]) (4 + [Pi])^(-4/[Pi])
(not Pi/4). I only tried to indicate, that MMA can't integrate if n>1/2
– Ulrich Neumann
2 days ago
1
1
@King.Max as you found, as it is Mathematica doesn't solve the limit. It needs some help (i.e. manual interference from the user). If my suggestion isn't acceptable to you, what kind of help would be acceptable? Maybe one could pass some options to
Limit
or to Integrate
, but I can't say for sure.– LLlAMnYP
2 days ago
@King.Max as you found, as it is Mathematica doesn't solve the limit. It needs some help (i.e. manual interference from the user). If my suggestion isn't acceptable to you, what kind of help would be acceptable? Maybe one could pass some options to
Limit
or to Integrate
, but I can't say for sure.– LLlAMnYP
2 days ago
1
1
Try:
Limit[n*Integrate[Tan[x/n]^n, x, 0, Pi/4, Assumptions -> n > 1]^(1/n) // PowerExpand, n -> Infinity]
– Mariusz Iwaniuk
2 days ago
Try:
Limit[n*Integrate[Tan[x/n]^n, x, 0, Pi/4, Assumptions -> n > 1]^(1/n) // PowerExpand, n -> Infinity]
– Mariusz Iwaniuk
2 days ago
 |Â
show 2 more comments
1 Answer
1
active
oldest
votes
up vote
6
down vote
Integrate
returns an anti-derivative which seems reasonable for large n
:
antiDeri = Integrate[Tan[x/n]^n, x];
Plot[antiDeri /. n -> 18, x, 0, À/4, PlotRange -> All]
And then
Limit[n Power[(antiDeri /. x -> À/4) - (antiDeri /. x -> 0), 1/n], n -> ∞]
À/4
how simple a tricky solution can be...
– Ulrich Neumann
2 days ago
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
6
down vote
Integrate
returns an anti-derivative which seems reasonable for large n
:
antiDeri = Integrate[Tan[x/n]^n, x];
Plot[antiDeri /. n -> 18, x, 0, À/4, PlotRange -> All]
And then
Limit[n Power[(antiDeri /. x -> À/4) - (antiDeri /. x -> 0), 1/n], n -> ∞]
À/4
how simple a tricky solution can be...
– Ulrich Neumann
2 days ago
add a comment |Â
up vote
6
down vote
Integrate
returns an anti-derivative which seems reasonable for large n
:
antiDeri = Integrate[Tan[x/n]^n, x];
Plot[antiDeri /. n -> 18, x, 0, À/4, PlotRange -> All]
And then
Limit[n Power[(antiDeri /. x -> À/4) - (antiDeri /. x -> 0), 1/n], n -> ∞]
À/4
how simple a tricky solution can be...
– Ulrich Neumann
2 days ago
add a comment |Â
up vote
6
down vote
up vote
6
down vote
Integrate
returns an anti-derivative which seems reasonable for large n
:
antiDeri = Integrate[Tan[x/n]^n, x];
Plot[antiDeri /. n -> 18, x, 0, À/4, PlotRange -> All]
And then
Limit[n Power[(antiDeri /. x -> À/4) - (antiDeri /. x -> 0), 1/n], n -> ∞]
À/4
Integrate
returns an anti-derivative which seems reasonable for large n
:
antiDeri = Integrate[Tan[x/n]^n, x];
Plot[antiDeri /. n -> 18, x, 0, À/4, PlotRange -> All]
And then
Limit[n Power[(antiDeri /. x -> À/4) - (antiDeri /. x -> 0), 1/n], n -> ∞]
À/4
answered 2 days ago


Coolwater
13.4k32150
13.4k32150
how simple a tricky solution can be...
– Ulrich Neumann
2 days ago
add a comment |Â
how simple a tricky solution can be...
– Ulrich Neumann
2 days ago
how simple a tricky solution can be...
– Ulrich Neumann
2 days ago
how simple a tricky solution can be...
– Ulrich Neumann
2 days ago
add a comment |Â
King.Max is a new contributor. Be nice, and check out our Code of Conduct.
King.Max is a new contributor. Be nice, and check out our Code of Conduct.
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If you try
Integrate[Tan[x/n]^n, x, 0, Pi/4]
MMA evaluates a ConditionalExpression which constrains0<n<1/2
. Might be the limit doesn't exist?– Ulrich Neumann
2 days ago
1
@UlrichNeumann I'm quite sure, it does exist. At
n->Infinity
we can probably replaceTan[x/n]
withx/n
, then the limit is solvable and givesPi/4
– LLlAMnYP
2 days ago
@LLlAMnYP The limit would be
1/4 [Pi]^((4 + [Pi])/[Pi]) (4 + [Pi])^(-4/[Pi])
(not Pi/4). I only tried to indicate, that MMA can't integrate ifn>1/2
– Ulrich Neumann
2 days ago
1
@King.Max as you found, as it is Mathematica doesn't solve the limit. It needs some help (i.e. manual interference from the user). If my suggestion isn't acceptable to you, what kind of help would be acceptable? Maybe one could pass some options to
Limit
or toIntegrate
, but I can't say for sure.– LLlAMnYP
2 days ago
1
Try:
Limit[n*Integrate[Tan[x/n]^n, x, 0, Pi/4, Assumptions -> n > 1]^(1/n) // PowerExpand, n -> Infinity]
– Mariusz Iwaniuk
2 days ago