Solve the Homogenous Differential Equations. (x-y \ln y+y \ln x)dx+x(\ln y-\ln

petrusrexcs

petrusrexcs

Answered question

2022-01-16

Solve the Homogenous Differential Equations.
(xylny+ylnx)dx+x(lnylnx)dy=0

Answer & Explanation

sonorous9n

sonorous9n

Beginner2022-01-17Added 34 answers

To solve the given homogeneous differential equation substitute y=vx and dydx=v+xdvdx. Then solve by using the variable separable method.
(xylny+ylnx)dx+x(lnylnx)dy=0
x(lnylnx)dy=(xylny+ylnx)dx
dydx=(x+ylnyylnx)x(lnylnx)
Put y=vx,dydx=v+xdvdx
v+xdvdx=x+vxln(vx)vxlnxx(ln(vx)lnx)
=x+vx(ln(vx)lnx)x(ln(vx)lnx)
=x+vxln(vxx)xln(vxx)
(Since ln(ab)=lnalnb)
=x+vxln(v)xln(x)
=x(1+vln(v))xln(v)
=1+vln(v)ln(v)
Marcus Herman

Marcus Herman

Beginner2022-01-18Added 41 answers

(xylny+ylnx)dx+x(lnylnx)dy=0
[xy(lnylnx)]dx+xln(yx)dy=0
(xyln(yx))dx+xln(yx)dy=0
x(1yxln(yx))dx+xln(yx)dy=0
(1yxln(yx)dx+ln(yx)dy=0
dydx=1yxln(yx)ln(yx)
This is homogeneous differential equation.
Now put yx=vy=vxdydx=v+xdvdx
we get v+xdvdx=1vlnvlnv
xdvdx=1vlnvlnvv
xdvdx=[1vlnv+vlnvlnv]
alenahelenash

alenahelenash

Expert2022-01-24Added 556 answers

(yylny+ylnx)dx+x(lnylnx)dy=0 xylny+ylnx+x(lnylnx)dydx=0 Substituting y=xv dydx=v+xdvdx xxvln(xv)+xvlnx+x(ln(xv)lnx)(v+xdvdx)=0 xxvln(xv)+xvln(x)+xvln(xv)xvlnx+x2ln(xv)dvdx x2ln(x)dvdx=0 x+x2dvdx[ln(xv)ln(x)]=0 x+x2dvdxln(v)=0 dvdx=1xln(v) ln(v)dv=1xdx Integrating both sides ln(v)dv=1xdx v+ln(v)v=ln(x)+c yx+ln(yx)yx=ln(x)+c y(ln(yx))y+xln(x)+cx=0

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