Find the value of $k$ for $f(x|y)$

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Let $Y$ a uniform random variable in $[0,1]$, and let $X$ a uniform variable in $[1,e^Y]$



Find $f(x|y)$ and $f_y(y)$



We know $Xsim mathcalU[1,e^Y]$ and $Ysim mathcalU[0,1]$ then by definition of uniform distribution, we have:



$f(x|y)= begincases k & 1 le x le e^y \0 & otherwise,\endcases$



and $f_y(y)=begincases t & 0 le y le 1 \0 & otherwise,\endcases$



Then, i need find the value of $t$ and $k$.



For $f_y(y)$ by definition of density function, $t=1$. But for $f(x|y)$ i'm stuck. Can someone help me?







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    up vote
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    Let $Y$ a uniform random variable in $[0,1]$, and let $X$ a uniform variable in $[1,e^Y]$



    Find $f(x|y)$ and $f_y(y)$



    We know $Xsim mathcalU[1,e^Y]$ and $Ysim mathcalU[0,1]$ then by definition of uniform distribution, we have:



    $f(x|y)= begincases k & 1 le x le e^y \0 & otherwise,\endcases$



    and $f_y(y)=begincases t & 0 le y le 1 \0 & otherwise,\endcases$



    Then, i need find the value of $t$ and $k$.



    For $f_y(y)$ by definition of density function, $t=1$. But for $f(x|y)$ i'm stuck. Can someone help me?







    share|cite|improve this question





















      up vote
      2
      down vote

      favorite









      up vote
      2
      down vote

      favorite











      Let $Y$ a uniform random variable in $[0,1]$, and let $X$ a uniform variable in $[1,e^Y]$



      Find $f(x|y)$ and $f_y(y)$



      We know $Xsim mathcalU[1,e^Y]$ and $Ysim mathcalU[0,1]$ then by definition of uniform distribution, we have:



      $f(x|y)= begincases k & 1 le x le e^y \0 & otherwise,\endcases$



      and $f_y(y)=begincases t & 0 le y le 1 \0 & otherwise,\endcases$



      Then, i need find the value of $t$ and $k$.



      For $f_y(y)$ by definition of density function, $t=1$. But for $f(x|y)$ i'm stuck. Can someone help me?







      share|cite|improve this question











      Let $Y$ a uniform random variable in $[0,1]$, and let $X$ a uniform variable in $[1,e^Y]$



      Find $f(x|y)$ and $f_y(y)$



      We know $Xsim mathcalU[1,e^Y]$ and $Ysim mathcalU[0,1]$ then by definition of uniform distribution, we have:



      $f(x|y)= begincases k & 1 le x le e^y \0 & otherwise,\endcases$



      and $f_y(y)=begincases t & 0 le y le 1 \0 & otherwise,\endcases$



      Then, i need find the value of $t$ and $k$.



      For $f_y(y)$ by definition of density function, $t=1$. But for $f(x|y)$ i'm stuck. Can someone help me?









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      asked Jul 15 at 23:40









      Orlian Prato

      275




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          The integral of a pdf from $-infty$ to $infty$ (the total area under the curve) must be 1. Therefore, $k$ is $(e^y-1)^-1$. Similarly for $t$.






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          • @Graham Kemp oops. Thanks. :)
            – NicNic8
            Jul 16 at 0:24










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          up vote
          2
          down vote













          The integral of a pdf from $-infty$ to $infty$ (the total area under the curve) must be 1. Therefore, $k$ is $(e^y-1)^-1$. Similarly for $t$.






          share|cite|improve this answer























          • @Graham Kemp oops. Thanks. :)
            – NicNic8
            Jul 16 at 0:24














          up vote
          2
          down vote













          The integral of a pdf from $-infty$ to $infty$ (the total area under the curve) must be 1. Therefore, $k$ is $(e^y-1)^-1$. Similarly for $t$.






          share|cite|improve this answer























          • @Graham Kemp oops. Thanks. :)
            – NicNic8
            Jul 16 at 0:24












          up vote
          2
          down vote










          up vote
          2
          down vote









          The integral of a pdf from $-infty$ to $infty$ (the total area under the curve) must be 1. Therefore, $k$ is $(e^y-1)^-1$. Similarly for $t$.






          share|cite|improve this answer















          The integral of a pdf from $-infty$ to $infty$ (the total area under the curve) must be 1. Therefore, $k$ is $(e^y-1)^-1$. Similarly for $t$.







          share|cite|improve this answer















          share|cite|improve this answer



          share|cite|improve this answer








          edited Jul 16 at 0:14









          Graham Kemp

          80.1k43275




          80.1k43275











          answered Jul 15 at 23:46









          NicNic8

          3,7113922




          3,7113922











          • @Graham Kemp oops. Thanks. :)
            – NicNic8
            Jul 16 at 0:24
















          • @Graham Kemp oops. Thanks. :)
            – NicNic8
            Jul 16 at 0:24















          @Graham Kemp oops. Thanks. :)
          – NicNic8
          Jul 16 at 0:24




          @Graham Kemp oops. Thanks. :)
          – NicNic8
          Jul 16 at 0:24












           

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