Marginal probability distribution of unit circle random variable












0












$begingroup$


I am given a task stating that there is a bivariate random vector X such that:
$$begin{equation}
p_x(x)=left{
begin{array}{@{}ll@{}}
frac1pi, & text{if} x^2+y^2 < 1 \
0, & text{otherwise}
end{array}right.
end{equation} $$

and I am asked to find margianl distribution with respect to X and Y.
I tried to catch it up by google and found some answers. e.g.
$$f(x)_x=int_sqrt{1^2-x^2}^sqrt{1^2+x^2}frac1pi dy$$
One thing I am interested in. Where the integration bounds came from. Can anyone explain pls?










share|cite|improve this question











$endgroup$












  • $begingroup$
    I find different limits: $- sqrt(1-x^2)$ and $sqrt(1-x^2)$
    $endgroup$
    – Carlos Campos
    Jan 9 at 19:35










  • $begingroup$
    Thanks, just realized that I can do in such way
    $endgroup$
    – Hillbilly Joe
    Jan 9 at 19:42
















0












$begingroup$


I am given a task stating that there is a bivariate random vector X such that:
$$begin{equation}
p_x(x)=left{
begin{array}{@{}ll@{}}
frac1pi, & text{if} x^2+y^2 < 1 \
0, & text{otherwise}
end{array}right.
end{equation} $$

and I am asked to find margianl distribution with respect to X and Y.
I tried to catch it up by google and found some answers. e.g.
$$f(x)_x=int_sqrt{1^2-x^2}^sqrt{1^2+x^2}frac1pi dy$$
One thing I am interested in. Where the integration bounds came from. Can anyone explain pls?










share|cite|improve this question











$endgroup$












  • $begingroup$
    I find different limits: $- sqrt(1-x^2)$ and $sqrt(1-x^2)$
    $endgroup$
    – Carlos Campos
    Jan 9 at 19:35










  • $begingroup$
    Thanks, just realized that I can do in such way
    $endgroup$
    – Hillbilly Joe
    Jan 9 at 19:42














0












0








0





$begingroup$


I am given a task stating that there is a bivariate random vector X such that:
$$begin{equation}
p_x(x)=left{
begin{array}{@{}ll@{}}
frac1pi, & text{if} x^2+y^2 < 1 \
0, & text{otherwise}
end{array}right.
end{equation} $$

and I am asked to find margianl distribution with respect to X and Y.
I tried to catch it up by google and found some answers. e.g.
$$f(x)_x=int_sqrt{1^2-x^2}^sqrt{1^2+x^2}frac1pi dy$$
One thing I am interested in. Where the integration bounds came from. Can anyone explain pls?










share|cite|improve this question











$endgroup$




I am given a task stating that there is a bivariate random vector X such that:
$$begin{equation}
p_x(x)=left{
begin{array}{@{}ll@{}}
frac1pi, & text{if} x^2+y^2 < 1 \
0, & text{otherwise}
end{array}right.
end{equation} $$

and I am asked to find margianl distribution with respect to X and Y.
I tried to catch it up by google and found some answers. e.g.
$$f(x)_x=int_sqrt{1^2-x^2}^sqrt{1^2+x^2}frac1pi dy$$
One thing I am interested in. Where the integration bounds came from. Can anyone explain pls?







probability probability-theory probability-distributions






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share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 9 at 19:16







Hillbilly Joe

















asked Jan 9 at 19:07









Hillbilly JoeHillbilly Joe

164




164












  • $begingroup$
    I find different limits: $- sqrt(1-x^2)$ and $sqrt(1-x^2)$
    $endgroup$
    – Carlos Campos
    Jan 9 at 19:35










  • $begingroup$
    Thanks, just realized that I can do in such way
    $endgroup$
    – Hillbilly Joe
    Jan 9 at 19:42


















  • $begingroup$
    I find different limits: $- sqrt(1-x^2)$ and $sqrt(1-x^2)$
    $endgroup$
    – Carlos Campos
    Jan 9 at 19:35










  • $begingroup$
    Thanks, just realized that I can do in such way
    $endgroup$
    – Hillbilly Joe
    Jan 9 at 19:42
















$begingroup$
I find different limits: $- sqrt(1-x^2)$ and $sqrt(1-x^2)$
$endgroup$
– Carlos Campos
Jan 9 at 19:35




$begingroup$
I find different limits: $- sqrt(1-x^2)$ and $sqrt(1-x^2)$
$endgroup$
– Carlos Campos
Jan 9 at 19:35












$begingroup$
Thanks, just realized that I can do in such way
$endgroup$
– Hillbilly Joe
Jan 9 at 19:42




$begingroup$
Thanks, just realized that I can do in such way
$endgroup$
– Hillbilly Joe
Jan 9 at 19:42










1 Answer
1






active

oldest

votes


















0












$begingroup$

Define the domain $mathcal{D} = {(x_1,x2) vert x_1^2 + x_2^2 <1}$. Given a fix $x_1$, if $(x_1, x_2)$ belongs to $mathcal{D}$, $x_2$ has to satisfy $ - sqrt{1-x_1^2}< x_2 < sqrt{1-x_1^2}$, where we are taken positive roots:



begin{equation}
f_{X_1}(x_1) = int_{D} f_{X_1,X_2}(x_1,x_2) d x_2 = left{
begin{array}{@{}ll@{}}
int_{- sqrt{1-x_1^2}}^{ sqrt{1-x_1^2}} frac{1}{pi} d x_2 = frac{2sqrt{1-x_1^2}}{pi} & text{if} x_1^2 < 1 \
0, & text{otherwise}
end{array}right.
end{equation}






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Thank you for your explanation.
    $endgroup$
    – Hillbilly Joe
    Jan 9 at 19:46











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









0












$begingroup$

Define the domain $mathcal{D} = {(x_1,x2) vert x_1^2 + x_2^2 <1}$. Given a fix $x_1$, if $(x_1, x_2)$ belongs to $mathcal{D}$, $x_2$ has to satisfy $ - sqrt{1-x_1^2}< x_2 < sqrt{1-x_1^2}$, where we are taken positive roots:



begin{equation}
f_{X_1}(x_1) = int_{D} f_{X_1,X_2}(x_1,x_2) d x_2 = left{
begin{array}{@{}ll@{}}
int_{- sqrt{1-x_1^2}}^{ sqrt{1-x_1^2}} frac{1}{pi} d x_2 = frac{2sqrt{1-x_1^2}}{pi} & text{if} x_1^2 < 1 \
0, & text{otherwise}
end{array}right.
end{equation}






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Thank you for your explanation.
    $endgroup$
    – Hillbilly Joe
    Jan 9 at 19:46
















0












$begingroup$

Define the domain $mathcal{D} = {(x_1,x2) vert x_1^2 + x_2^2 <1}$. Given a fix $x_1$, if $(x_1, x_2)$ belongs to $mathcal{D}$, $x_2$ has to satisfy $ - sqrt{1-x_1^2}< x_2 < sqrt{1-x_1^2}$, where we are taken positive roots:



begin{equation}
f_{X_1}(x_1) = int_{D} f_{X_1,X_2}(x_1,x_2) d x_2 = left{
begin{array}{@{}ll@{}}
int_{- sqrt{1-x_1^2}}^{ sqrt{1-x_1^2}} frac{1}{pi} d x_2 = frac{2sqrt{1-x_1^2}}{pi} & text{if} x_1^2 < 1 \
0, & text{otherwise}
end{array}right.
end{equation}






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Thank you for your explanation.
    $endgroup$
    – Hillbilly Joe
    Jan 9 at 19:46














0












0








0





$begingroup$

Define the domain $mathcal{D} = {(x_1,x2) vert x_1^2 + x_2^2 <1}$. Given a fix $x_1$, if $(x_1, x_2)$ belongs to $mathcal{D}$, $x_2$ has to satisfy $ - sqrt{1-x_1^2}< x_2 < sqrt{1-x_1^2}$, where we are taken positive roots:



begin{equation}
f_{X_1}(x_1) = int_{D} f_{X_1,X_2}(x_1,x_2) d x_2 = left{
begin{array}{@{}ll@{}}
int_{- sqrt{1-x_1^2}}^{ sqrt{1-x_1^2}} frac{1}{pi} d x_2 = frac{2sqrt{1-x_1^2}}{pi} & text{if} x_1^2 < 1 \
0, & text{otherwise}
end{array}right.
end{equation}






share|cite|improve this answer









$endgroup$



Define the domain $mathcal{D} = {(x_1,x2) vert x_1^2 + x_2^2 <1}$. Given a fix $x_1$, if $(x_1, x_2)$ belongs to $mathcal{D}$, $x_2$ has to satisfy $ - sqrt{1-x_1^2}< x_2 < sqrt{1-x_1^2}$, where we are taken positive roots:



begin{equation}
f_{X_1}(x_1) = int_{D} f_{X_1,X_2}(x_1,x_2) d x_2 = left{
begin{array}{@{}ll@{}}
int_{- sqrt{1-x_1^2}}^{ sqrt{1-x_1^2}} frac{1}{pi} d x_2 = frac{2sqrt{1-x_1^2}}{pi} & text{if} x_1^2 < 1 \
0, & text{otherwise}
end{array}right.
end{equation}







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Jan 9 at 19:42









Carlos CamposCarlos Campos

57439




57439












  • $begingroup$
    Thank you for your explanation.
    $endgroup$
    – Hillbilly Joe
    Jan 9 at 19:46


















  • $begingroup$
    Thank you for your explanation.
    $endgroup$
    – Hillbilly Joe
    Jan 9 at 19:46
















$begingroup$
Thank you for your explanation.
$endgroup$
– Hillbilly Joe
Jan 9 at 19:46




$begingroup$
Thank you for your explanation.
$endgroup$
– Hillbilly Joe
Jan 9 at 19:46


















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