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Find the solution of the differential equation that satisfies the given initial condition. dy/dx=x/y , y(0)=-1

User Anroots
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1 Answer

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Separating variables, we have


(dy)/(dx) = \frac xy \implies y\,dy = x\,dx

Integrate both sides.


\displaystyle \int y\,dy = \int x\,dx


\frac12 y^2 = \frac12 x^2 + C

Given that
y(0)=-1, we find


\frac12 (-1)^2 = \frac12 0^2 + C \implies C = \frac12

Then the particular solution is


\frac12 y^2 = \frac12 x^2 + \frac12


y^2 = x^2 + 1


y = \pm√(x^2 + 1)

and because
y(0)=-1, we take the negative solution to accommodate this initial value.


\boxed{y(x) = -√(x^2+1)}

User Damjan
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