Wednesday, March 27, 2013

`dy/dx = x/y` Find the general solution of the differential equation

`(dy)/dx = x/y`


This differential equation is separable since it can be re-written in the form



  • `N(y)dy = M(x)dx`

So separating the variables, the equation becomes


`ydy = xdx`


Integrating both sides, it result to


`int y dy = int x dx`


`y^2/2 + C_1 = x^2/2 + C_2`


Isolating the y, it becomes


`y^2/2 =x^2/2+C_2-C_1`


`y^2=x^2 + 2C_2 - 2C_1`


`y=+-sqrt(x^2+2C_2-2C_1)`


Since C2 and C1 represents any number, it can be expressed as a single constant C.


`y = +-sqrt(x^2+C)`



Therefore, the general solution of the given differential equation is `y = +-sqrt(x^2+C)` .

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