Question #292328

ydx+2(y^4-x)dy=0


1
Expert's answer
2022-02-01T07:35:03-0500

The given equation can be written as y dx=2(y4x)dyy~dx = -2(y^{4} - x)dy. It would be easier to solve this equation in terms of dxdy.\frac{dx}{dy}.


dxdy=(2y4x)y=2y3+2xydxdy2xy=2y3\dfrac{dx}{dy} = -\dfrac{(2y^{4} - x)}{y} = -2y^3 + \dfrac{2x}{y}\\ \dfrac{dx}{dy} - \dfrac{2x}{y} = -2y^3 \\

which is of the form

dxdy+P(y)x=Q(y).\dfrac{dx}{dy} + P(y)x = Q(y).

whose solution is given by xePdy=QePdydy+cxe^{\int Pdy} = \int Q e^{\int Pdy} dy + c, where ePdye^{\int Pdy}  is called the integrating factor.


Here P(y)=2yP(y) = -\frac{2}{y} and ePdy=e2y=1y2e^{\int Pdy} = e^{\int \frac{-2}{y}} = \frac{1}{y^{2}}. Hence the solution of the given equation is


xy2=2y31y2dy+cxy2=2ydy+cxy2=y2+cx=cy2y4\dfrac{x}{y^{2}} = \int -2y^{3} \cdot \frac{1}{y^{2}}dy + c\\ \dfrac{x}{y^{2}} = \int -2y dy + c\\ \dfrac{x}{y^{2}} = -y^{2} + c\\ \therefore x = cy^{2} - y^{4}


Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!

Comments

No comments. Be the first!
LATEST TUTORIALS
APPROVED BY CLIENTS