Differential Equation linear, separable, neither or both?











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I am stuck on deciding whether or not the differential equation
$$frac{dy}{dx} = frac{1}{x} + frac{1}{y}$$ is linear or separable? I believe it is linear although I am confused on the value of $P(x)$ since $frac{1}{y} < y$.
Any help would be appreciated










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  • What is $P(x)$?
    – the_candyman
    Nov 15 at 23:28















up vote
0
down vote

favorite












I am stuck on deciding whether or not the differential equation
$$frac{dy}{dx} = frac{1}{x} + frac{1}{y}$$ is linear or separable? I believe it is linear although I am confused on the value of $P(x)$ since $frac{1}{y} < y$.
Any help would be appreciated










share|cite|improve this question
























  • What is $P(x)$?
    – the_candyman
    Nov 15 at 23:28













up vote
0
down vote

favorite









up vote
0
down vote

favorite











I am stuck on deciding whether or not the differential equation
$$frac{dy}{dx} = frac{1}{x} + frac{1}{y}$$ is linear or separable? I believe it is linear although I am confused on the value of $P(x)$ since $frac{1}{y} < y$.
Any help would be appreciated










share|cite|improve this question















I am stuck on deciding whether or not the differential equation
$$frac{dy}{dx} = frac{1}{x} + frac{1}{y}$$ is linear or separable? I believe it is linear although I am confused on the value of $P(x)$ since $frac{1}{y} < y$.
Any help would be appreciated







calculus differential-equations






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edited Nov 15 at 23:17









the_candyman

8,55921944




8,55921944










asked Nov 15 at 23:15









ilovesports524

21




21












  • What is $P(x)$?
    – the_candyman
    Nov 15 at 23:28


















  • What is $P(x)$?
    – the_candyman
    Nov 15 at 23:28
















What is $P(x)$?
– the_candyman
Nov 15 at 23:28




What is $P(x)$?
– the_candyman
Nov 15 at 23:28










2 Answers
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For sure, it is not linear. Check this link to understand the meaning of linearity.
Moreover, it is not separable, since you can not rewrite it as:



$$frac{dy}{dx} = f(y)g(x).$$



In fact:



$$frac{1}{x} + frac{1}{y} = frac{x+y}{xy} neq f(y)g(x).$$






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    up vote
    0
    down vote













    The standard form of a first order linear differential equation in $(y,x)$ is given as ,



    $frac{dy}{dx}+P(x)y=Q(x)$.



    Since your equation cannot be written as above equation.



    So your equation is not linear in $(y,x)$.



    Hence $P(x)$ does not exist.



    As @the_candyman showed that it is not a separable too.






    share|cite|improve this answer





















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      2 Answers
      2






      active

      oldest

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      2 Answers
      2






      active

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      up vote
      0
      down vote













      For sure, it is not linear. Check this link to understand the meaning of linearity.
      Moreover, it is not separable, since you can not rewrite it as:



      $$frac{dy}{dx} = f(y)g(x).$$



      In fact:



      $$frac{1}{x} + frac{1}{y} = frac{x+y}{xy} neq f(y)g(x).$$






      share|cite|improve this answer

























        up vote
        0
        down vote













        For sure, it is not linear. Check this link to understand the meaning of linearity.
        Moreover, it is not separable, since you can not rewrite it as:



        $$frac{dy}{dx} = f(y)g(x).$$



        In fact:



        $$frac{1}{x} + frac{1}{y} = frac{x+y}{xy} neq f(y)g(x).$$






        share|cite|improve this answer























          up vote
          0
          down vote










          up vote
          0
          down vote









          For sure, it is not linear. Check this link to understand the meaning of linearity.
          Moreover, it is not separable, since you can not rewrite it as:



          $$frac{dy}{dx} = f(y)g(x).$$



          In fact:



          $$frac{1}{x} + frac{1}{y} = frac{x+y}{xy} neq f(y)g(x).$$






          share|cite|improve this answer












          For sure, it is not linear. Check this link to understand the meaning of linearity.
          Moreover, it is not separable, since you can not rewrite it as:



          $$frac{dy}{dx} = f(y)g(x).$$



          In fact:



          $$frac{1}{x} + frac{1}{y} = frac{x+y}{xy} neq f(y)g(x).$$







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Nov 15 at 23:26









          the_candyman

          8,55921944




          8,55921944






















              up vote
              0
              down vote













              The standard form of a first order linear differential equation in $(y,x)$ is given as ,



              $frac{dy}{dx}+P(x)y=Q(x)$.



              Since your equation cannot be written as above equation.



              So your equation is not linear in $(y,x)$.



              Hence $P(x)$ does not exist.



              As @the_candyman showed that it is not a separable too.






              share|cite|improve this answer

























                up vote
                0
                down vote













                The standard form of a first order linear differential equation in $(y,x)$ is given as ,



                $frac{dy}{dx}+P(x)y=Q(x)$.



                Since your equation cannot be written as above equation.



                So your equation is not linear in $(y,x)$.



                Hence $P(x)$ does not exist.



                As @the_candyman showed that it is not a separable too.






                share|cite|improve this answer























                  up vote
                  0
                  down vote










                  up vote
                  0
                  down vote









                  The standard form of a first order linear differential equation in $(y,x)$ is given as ,



                  $frac{dy}{dx}+P(x)y=Q(x)$.



                  Since your equation cannot be written as above equation.



                  So your equation is not linear in $(y,x)$.



                  Hence $P(x)$ does not exist.



                  As @the_candyman showed that it is not a separable too.






                  share|cite|improve this answer












                  The standard form of a first order linear differential equation in $(y,x)$ is given as ,



                  $frac{dy}{dx}+P(x)y=Q(x)$.



                  Since your equation cannot be written as above equation.



                  So your equation is not linear in $(y,x)$.



                  Hence $P(x)$ does not exist.



                  As @the_candyman showed that it is not a separable too.







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered Nov 16 at 11:39









                  Sachin Kumar

                  20518




                  20518






























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