Solve the following equation? (x-2xy-y^{2})\frac{dy}{dx}+y^{2}=0



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Solve the following equation?

Answer & Explanation



Beginner2022-01-18Added 40 answers

For this one we look for an integrating factor which will make the equation exact.
Let M=x2xyy2 and N=y2. Then Mx=12y and Ny=2y.
Thus MxNyN=12yy2=1y221y
which is purely a function of y. This tells us that there is an integrating factor μ(y) which makes the equation exact which satisfies
Clearly μ(y)=e(1y221y)dy=e1y2logy=y2ey1.
Try (first checking that my algebra is correct) and then multiplying the differential equation by this integrating factor, it should become an exact differential equation which I'm guessing you know how to solve if you are asking this question.
Cleveland Walters

Cleveland Walters

Beginner2022-01-19Added 40 answers

Hint: Your equation can be turned into a first order linear differential equation in dxdy (i.e., just multiply the equation by dxdy and it is a standard form....)


Expert2022-01-24Added 556 answers

As it looks some people misunderstood (I apologize, the fault may be my side) my first answer, here is the complete solution after reducing the problem into standard form: As I wrote in the first answer, multiplying both sides by dxdy (the hint was that it will make the equation linear in x), dxdy+(12yy2)x=1. This is a linear equation (in x) of the standard form dxdy+P(y)x=Q(x). So, eP(y)dy=e(12yy2)dy=e1yy2 is an integrating factor (IF). So, multiplying by the IF and integrating the general solution is given by xe1yy2=e1yy2dy+c=e1y+c Or, x=y2(1+ce1y).

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