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Differential Equations 10 Online
OpenStudy (nvafer):

bernoullis equation

OpenStudy (nvafer):

\[6y^2dx−x(2x^3+y)dy=0\]

OpenStudy (nvafer):

find the solution

OpenStudy (nvafer):

the general solution

OpenStudy (nvafer):

http://tutorial.math.lamar.edu/Classes/DE/Bernoulli.aspx I know how to do it,but i dont get the right answer thats why i need help

OpenStudy (unklerhaukus):

i don't think that is a Bernoulli equation

OpenStudy (irishboy123):

i think you're right, sir. not Bernoulli

OpenStudy (holsteremission):

Solving for \(\dfrac{\mathrm dx}{\mathrm dy}\), we can see that the ODE is indeed a Bernoulli equation. \[\begin{align*}6y^2\,\mathrm dx-x(2x^3+y)\,\mathrm dy=0\implies\quad \quad \quad\frac{\mathrm dx}{\mathrm dy}-\frac{1}{6y}x&=\frac{1}{3y^2}x^4\\[1ex] x^{-4}\frac{\mathrm dx}{\mathrm dy}-\frac{1}{6y}x^{-3}&=\frac{1}{3y^2} \end{align*}\]Set \(u=x^{-3}\), so \(-\dfrac{1}{4}\dfrac{\mathrm du}{\mathrm dy}=x^{-4}\dfrac{\mathrm dx}{\mathrm dy}\). The ODE becomes \[\begin{align*} -\frac{1}{4}\frac{\mathrm du}{\mathrm dy}-\frac{1}{6y}u&=\frac{1}{3y^2}\\[1ex] \frac{\mathrm du}{\mathrm dy}+\frac{2}{3}u&=-\frac{4}{3y^2} \end{align*}\]which is linear in \(u\).

OpenStudy (irishboy123):

you star!!

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