Calculating the integral $int_{-infty}^inftyprodlimits_{i=1}^ne^{-(y-v_i)}e^{-e^{-(y-v_i)}}dy$












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I'm a little rusty with my calculus so I was hoping if anyone would help me with the following integral:



$$int_{-infty}^{infty} prod _{i=1}^ne^{-(y-v_i)}e^{-e^{-(y-v_i)}}dy$$










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    1












    $begingroup$


    I'm a little rusty with my calculus so I was hoping if anyone would help me with the following integral:



    $$int_{-infty}^{infty} prod _{i=1}^ne^{-(y-v_i)}e^{-e^{-(y-v_i)}}dy$$










    share|cite|improve this question











    $endgroup$















      1












      1








      1





      $begingroup$


      I'm a little rusty with my calculus so I was hoping if anyone would help me with the following integral:



      $$int_{-infty}^{infty} prod _{i=1}^ne^{-(y-v_i)}e^{-e^{-(y-v_i)}}dy$$










      share|cite|improve this question











      $endgroup$




      I'm a little rusty with my calculus so I was hoping if anyone would help me with the following integral:



      $$int_{-infty}^{infty} prod _{i=1}^ne^{-(y-v_i)}e^{-e^{-(y-v_i)}}dy$$







      calculus integration






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      share|cite|improve this question













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      edited Jan 11 at 22:07









      Did

      248k23225463




      248k23225463










      asked Mar 23 '12 at 15:28









      user25720user25720

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          $begingroup$

          Using $x=mathrm e^{-y}$, the integral you are interested in is
          $$
          I=int_0^{+infty}prod_{i=1}^nleft(xmathrm e^{v_i}cdotmathrm e^{-mathrm e^{v_i}x}right)cdotfrac{mathrm dx}x=int_0^{+infty}ax^{n-1}mathrm e^{-bx}mathrm dx,
          $$
          for some suitable positive $a$ and $b$, depending on $(v_i)_{1leqslant ileqslant n}$, that I will let you discover. Thus,
          $$
          I=int_0^{+infty}ab^{-n}x^{n-1}mathrm e^{-x}mathrm dx=(n-1)!cdot ab^{-n}.
          $$






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            $begingroup$

            Using $x=mathrm e^{-y}$, the integral you are interested in is
            $$
            I=int_0^{+infty}prod_{i=1}^nleft(xmathrm e^{v_i}cdotmathrm e^{-mathrm e^{v_i}x}right)cdotfrac{mathrm dx}x=int_0^{+infty}ax^{n-1}mathrm e^{-bx}mathrm dx,
            $$
            for some suitable positive $a$ and $b$, depending on $(v_i)_{1leqslant ileqslant n}$, that I will let you discover. Thus,
            $$
            I=int_0^{+infty}ab^{-n}x^{n-1}mathrm e^{-x}mathrm dx=(n-1)!cdot ab^{-n}.
            $$






            share|cite|improve this answer









            $endgroup$


















              4












              $begingroup$

              Using $x=mathrm e^{-y}$, the integral you are interested in is
              $$
              I=int_0^{+infty}prod_{i=1}^nleft(xmathrm e^{v_i}cdotmathrm e^{-mathrm e^{v_i}x}right)cdotfrac{mathrm dx}x=int_0^{+infty}ax^{n-1}mathrm e^{-bx}mathrm dx,
              $$
              for some suitable positive $a$ and $b$, depending on $(v_i)_{1leqslant ileqslant n}$, that I will let you discover. Thus,
              $$
              I=int_0^{+infty}ab^{-n}x^{n-1}mathrm e^{-x}mathrm dx=(n-1)!cdot ab^{-n}.
              $$






              share|cite|improve this answer









              $endgroup$
















                4












                4








                4





                $begingroup$

                Using $x=mathrm e^{-y}$, the integral you are interested in is
                $$
                I=int_0^{+infty}prod_{i=1}^nleft(xmathrm e^{v_i}cdotmathrm e^{-mathrm e^{v_i}x}right)cdotfrac{mathrm dx}x=int_0^{+infty}ax^{n-1}mathrm e^{-bx}mathrm dx,
                $$
                for some suitable positive $a$ and $b$, depending on $(v_i)_{1leqslant ileqslant n}$, that I will let you discover. Thus,
                $$
                I=int_0^{+infty}ab^{-n}x^{n-1}mathrm e^{-x}mathrm dx=(n-1)!cdot ab^{-n}.
                $$






                share|cite|improve this answer









                $endgroup$



                Using $x=mathrm e^{-y}$, the integral you are interested in is
                $$
                I=int_0^{+infty}prod_{i=1}^nleft(xmathrm e^{v_i}cdotmathrm e^{-mathrm e^{v_i}x}right)cdotfrac{mathrm dx}x=int_0^{+infty}ax^{n-1}mathrm e^{-bx}mathrm dx,
                $$
                for some suitable positive $a$ and $b$, depending on $(v_i)_{1leqslant ileqslant n}$, that I will let you discover. Thus,
                $$
                I=int_0^{+infty}ab^{-n}x^{n-1}mathrm e^{-x}mathrm dx=(n-1)!cdot ab^{-n}.
                $$







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Mar 23 '12 at 15:38









                DidDid

                248k23225463




                248k23225463






























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