Integral $int_{[1,2]times[0,pi]}log(sqrt{x})sin(2y)d(x,y)$












0














I want to find out if this integral can be calculated (if it exists)



$$int_{[1,2]times[0,pi]} log(sqrt{x})sin(2y)~d(x,y)$$



To be honest, I don't know how, but I think that one might has to use Fubini's theorem since this is an iterated integral. Does someone know how it's done? And can someone explain to me what is meant with the interval $[1,2]times[0,pi]$?



I did this, but I don't know how to continue.



$$int_{[1,2]times[0,pi]} log(sqrt{x})sin(2y)~d(x,y) = dfrac{sinleft(2yright)lnleft(xright)}{2} = frac{sin(2y)}{2} int{ln(x)}~dx$$



Here's what the function looks like, it looks nice imo.



enter image description here










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  • What does $d(x,y)$ mean? Do you mean $dxdy$?
    – Mostafa Ayaz
    Dec 3 '18 at 22:18






  • 1




    The integral is obviously zero.
    – Did
    Dec 3 '18 at 23:30
















0














I want to find out if this integral can be calculated (if it exists)



$$int_{[1,2]times[0,pi]} log(sqrt{x})sin(2y)~d(x,y)$$



To be honest, I don't know how, but I think that one might has to use Fubini's theorem since this is an iterated integral. Does someone know how it's done? And can someone explain to me what is meant with the interval $[1,2]times[0,pi]$?



I did this, but I don't know how to continue.



$$int_{[1,2]times[0,pi]} log(sqrt{x})sin(2y)~d(x,y) = dfrac{sinleft(2yright)lnleft(xright)}{2} = frac{sin(2y)}{2} int{ln(x)}~dx$$



Here's what the function looks like, it looks nice imo.



enter image description here










share|cite|improve this question
























  • What does $d(x,y)$ mean? Do you mean $dxdy$?
    – Mostafa Ayaz
    Dec 3 '18 at 22:18






  • 1




    The integral is obviously zero.
    – Did
    Dec 3 '18 at 23:30














0












0








0







I want to find out if this integral can be calculated (if it exists)



$$int_{[1,2]times[0,pi]} log(sqrt{x})sin(2y)~d(x,y)$$



To be honest, I don't know how, but I think that one might has to use Fubini's theorem since this is an iterated integral. Does someone know how it's done? And can someone explain to me what is meant with the interval $[1,2]times[0,pi]$?



I did this, but I don't know how to continue.



$$int_{[1,2]times[0,pi]} log(sqrt{x})sin(2y)~d(x,y) = dfrac{sinleft(2yright)lnleft(xright)}{2} = frac{sin(2y)}{2} int{ln(x)}~dx$$



Here's what the function looks like, it looks nice imo.



enter image description here










share|cite|improve this question















I want to find out if this integral can be calculated (if it exists)



$$int_{[1,2]times[0,pi]} log(sqrt{x})sin(2y)~d(x,y)$$



To be honest, I don't know how, but I think that one might has to use Fubini's theorem since this is an iterated integral. Does someone know how it's done? And can someone explain to me what is meant with the interval $[1,2]times[0,pi]$?



I did this, but I don't know how to continue.



$$int_{[1,2]times[0,pi]} log(sqrt{x})sin(2y)~d(x,y) = dfrac{sinleft(2yright)lnleft(xright)}{2} = frac{sin(2y)}{2} int{ln(x)}~dx$$



Here's what the function looks like, it looks nice imo.



enter image description here







integration analysis functions iterated-integrals






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edited Dec 4 '18 at 10:13









Asaf Karagila

302k32426756




302k32426756










asked Dec 3 '18 at 22:15









Ramanujan Taylor

184




184












  • What does $d(x,y)$ mean? Do you mean $dxdy$?
    – Mostafa Ayaz
    Dec 3 '18 at 22:18






  • 1




    The integral is obviously zero.
    – Did
    Dec 3 '18 at 23:30


















  • What does $d(x,y)$ mean? Do you mean $dxdy$?
    – Mostafa Ayaz
    Dec 3 '18 at 22:18






  • 1




    The integral is obviously zero.
    – Did
    Dec 3 '18 at 23:30
















What does $d(x,y)$ mean? Do you mean $dxdy$?
– Mostafa Ayaz
Dec 3 '18 at 22:18




What does $d(x,y)$ mean? Do you mean $dxdy$?
– Mostafa Ayaz
Dec 3 '18 at 22:18




1




1




The integral is obviously zero.
– Did
Dec 3 '18 at 23:30




The integral is obviously zero.
– Did
Dec 3 '18 at 23:30










1 Answer
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Hint: the integral means $int_1^2 int_0^{pi}$. Further,
$$int_1^2int_0^pi f(x)g(y),dy,dx = left(int_1^2 f(x),dxright)left(int_0^pi g(y),dyright).$$






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    1 Answer
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    active

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    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    2














    Hint: the integral means $int_1^2 int_0^{pi}$. Further,
    $$int_1^2int_0^pi f(x)g(y),dy,dx = left(int_1^2 f(x),dxright)left(int_0^pi g(y),dyright).$$






    share|cite|improve this answer


























      2














      Hint: the integral means $int_1^2 int_0^{pi}$. Further,
      $$int_1^2int_0^pi f(x)g(y),dy,dx = left(int_1^2 f(x),dxright)left(int_0^pi g(y),dyright).$$






      share|cite|improve this answer
























        2












        2








        2






        Hint: the integral means $int_1^2 int_0^{pi}$. Further,
        $$int_1^2int_0^pi f(x)g(y),dy,dx = left(int_1^2 f(x),dxright)left(int_0^pi g(y),dyright).$$






        share|cite|improve this answer












        Hint: the integral means $int_1^2 int_0^{pi}$. Further,
        $$int_1^2int_0^pi f(x)g(y),dy,dx = left(int_1^2 f(x),dxright)left(int_0^pi g(y),dyright).$$







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Dec 3 '18 at 23:27









        rogerl

        17.4k22746




        17.4k22746






























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