How do I evaluate this double integral by changing the order of integration?
Clash Royale CLAN TAG#URR8PPP
up vote
-1
down vote
favorite
One of my past papers has the following question (without a solution).
Evaluate the integral by changing the order of integration.
$int_0^1dx$$int_x^1/a^1e^y^a+1dy$
where $a$ is a constant and $a neq -1, 0$.
I would assume changing the order of integration would make it easier to do but I can't see this.
integration multivariable-calculus
add a comment |Â
up vote
-1
down vote
favorite
One of my past papers has the following question (without a solution).
Evaluate the integral by changing the order of integration.
$int_0^1dx$$int_x^1/a^1e^y^a+1dy$
where $a$ is a constant and $a neq -1, 0$.
I would assume changing the order of integration would make it easier to do but I can't see this.
integration multivariable-calculus
1
Try it for $a=2$ and get back to us with where you get stuck.
– B. Goddard
Jul 24 at 17:10
add a comment |Â
up vote
-1
down vote
favorite
up vote
-1
down vote
favorite
One of my past papers has the following question (without a solution).
Evaluate the integral by changing the order of integration.
$int_0^1dx$$int_x^1/a^1e^y^a+1dy$
where $a$ is a constant and $a neq -1, 0$.
I would assume changing the order of integration would make it easier to do but I can't see this.
integration multivariable-calculus
One of my past papers has the following question (without a solution).
Evaluate the integral by changing the order of integration.
$int_0^1dx$$int_x^1/a^1e^y^a+1dy$
where $a$ is a constant and $a neq -1, 0$.
I would assume changing the order of integration would make it easier to do but I can't see this.
integration multivariable-calculus
asked Jul 24 at 17:03


user499701
777
777
1
Try it for $a=2$ and get back to us with where you get stuck.
– B. Goddard
Jul 24 at 17:10
add a comment |Â
1
Try it for $a=2$ and get back to us with where you get stuck.
– B. Goddard
Jul 24 at 17:10
1
1
Try it for $a=2$ and get back to us with where you get stuck.
– B. Goddard
Jul 24 at 17:10
Try it for $a=2$ and get back to us with where you get stuck.
– B. Goddard
Jul 24 at 17:10
add a comment |Â
2 Answers
2
active
oldest
votes
up vote
1
down vote
accepted
Draw on a graph and convince yourself that the region bounded by $x = 0 , x = 1$ and $y$ varying from $x^1/a$ to $1$ is same as the region enclosed by $y =0, y = 1$, and $x$ varying from $0$ to $y^a$, and change the integral accordingly
add a comment |Â
up vote
1
down vote
From $x^frac1aleq yleq1$ we have $xleq y^aleq1$ and also $0leq yleq1$ then the integral is
$$int_0^1,mathrmdyint_0^y^ae^y^a+1,mathrmdx=int_0^1,y^a,e^y^a+1,mathrmdy=colorbluedfrac1a+1(e-1)$$
How did you get $0leq yleq1$?
– user499701
Jul 24 at 17:26
Simply $0leq xleq y^aleq1$.
– Nosrati
Jul 24 at 17:34
Downvote means "the answer isn't useful.
– Nosrati
Jul 24 at 17:35
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
accepted
Draw on a graph and convince yourself that the region bounded by $x = 0 , x = 1$ and $y$ varying from $x^1/a$ to $1$ is same as the region enclosed by $y =0, y = 1$, and $x$ varying from $0$ to $y^a$, and change the integral accordingly
add a comment |Â
up vote
1
down vote
accepted
Draw on a graph and convince yourself that the region bounded by $x = 0 , x = 1$ and $y$ varying from $x^1/a$ to $1$ is same as the region enclosed by $y =0, y = 1$, and $x$ varying from $0$ to $y^a$, and change the integral accordingly
add a comment |Â
up vote
1
down vote
accepted
up vote
1
down vote
accepted
Draw on a graph and convince yourself that the region bounded by $x = 0 , x = 1$ and $y$ varying from $x^1/a$ to $1$ is same as the region enclosed by $y =0, y = 1$, and $x$ varying from $0$ to $y^a$, and change the integral accordingly
Draw on a graph and convince yourself that the region bounded by $x = 0 , x = 1$ and $y$ varying from $x^1/a$ to $1$ is same as the region enclosed by $y =0, y = 1$, and $x$ varying from $0$ to $y^a$, and change the integral accordingly
edited Jul 24 at 17:50
answered Jul 24 at 17:28
ab123
1,344319
1,344319
add a comment |Â
add a comment |Â
up vote
1
down vote
From $x^frac1aleq yleq1$ we have $xleq y^aleq1$ and also $0leq yleq1$ then the integral is
$$int_0^1,mathrmdyint_0^y^ae^y^a+1,mathrmdx=int_0^1,y^a,e^y^a+1,mathrmdy=colorbluedfrac1a+1(e-1)$$
How did you get $0leq yleq1$?
– user499701
Jul 24 at 17:26
Simply $0leq xleq y^aleq1$.
– Nosrati
Jul 24 at 17:34
Downvote means "the answer isn't useful.
– Nosrati
Jul 24 at 17:35
add a comment |Â
up vote
1
down vote
From $x^frac1aleq yleq1$ we have $xleq y^aleq1$ and also $0leq yleq1$ then the integral is
$$int_0^1,mathrmdyint_0^y^ae^y^a+1,mathrmdx=int_0^1,y^a,e^y^a+1,mathrmdy=colorbluedfrac1a+1(e-1)$$
How did you get $0leq yleq1$?
– user499701
Jul 24 at 17:26
Simply $0leq xleq y^aleq1$.
– Nosrati
Jul 24 at 17:34
Downvote means "the answer isn't useful.
– Nosrati
Jul 24 at 17:35
add a comment |Â
up vote
1
down vote
up vote
1
down vote
From $x^frac1aleq yleq1$ we have $xleq y^aleq1$ and also $0leq yleq1$ then the integral is
$$int_0^1,mathrmdyint_0^y^ae^y^a+1,mathrmdx=int_0^1,y^a,e^y^a+1,mathrmdy=colorbluedfrac1a+1(e-1)$$
From $x^frac1aleq yleq1$ we have $xleq y^aleq1$ and also $0leq yleq1$ then the integral is
$$int_0^1,mathrmdyint_0^y^ae^y^a+1,mathrmdx=int_0^1,y^a,e^y^a+1,mathrmdy=colorbluedfrac1a+1(e-1)$$
edited Jul 24 at 17:39
answered Jul 24 at 17:15


Nosrati
19.3k41544
19.3k41544
How did you get $0leq yleq1$?
– user499701
Jul 24 at 17:26
Simply $0leq xleq y^aleq1$.
– Nosrati
Jul 24 at 17:34
Downvote means "the answer isn't useful.
– Nosrati
Jul 24 at 17:35
add a comment |Â
How did you get $0leq yleq1$?
– user499701
Jul 24 at 17:26
Simply $0leq xleq y^aleq1$.
– Nosrati
Jul 24 at 17:34
Downvote means "the answer isn't useful.
– Nosrati
Jul 24 at 17:35
How did you get $0leq yleq1$?
– user499701
Jul 24 at 17:26
How did you get $0leq yleq1$?
– user499701
Jul 24 at 17:26
Simply $0leq xleq y^aleq1$.
– Nosrati
Jul 24 at 17:34
Simply $0leq xleq y^aleq1$.
– Nosrati
Jul 24 at 17:34
Downvote means "the answer isn't useful.
– Nosrati
Jul 24 at 17:35
Downvote means "the answer isn't useful.
– Nosrati
Jul 24 at 17:35
add a comment |Â
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2861553%2fhow-do-i-evaluate-this-double-integral-by-changing-the-order-of-integration%23new-answer', 'question_page');
);
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
1
Try it for $a=2$ and get back to us with where you get stuck.
– B. Goddard
Jul 24 at 17:10