Given equation is `y'+y/x=xy^2`
An equation of the form `y'+Py=Qy^n`
is called as the Bernoulli equation .
so, to proceed to solve this equation we have to transform the equation into a linear equation form of first order as follows
=>` y' (y^-n) +P y^(1-n)=Q`
let `u= y^(1-n)`
=> `(1-n)y^(-n)y'=u'`
=> `y^(-n)y' = (u')/(1-n)`
so ,
`y' (y^-n) +P y^(1-n)=Q`
=> `(u')/(1-n) +P u =Q `
so this equation is now of the linear form of first order
Now,
From this equation ,
`y'+y/x=xy^2`
and
`y'+Py=Qy^n`
on comparing we get
`P=(1/x) , Q=x , n=2`
so the linear form of first order of the equation `y'+y/x=xy^2 ` is given as
=> `(u')/(1-n) +P u =Q ` where` u= y^(1-n) =y^(1-2)=1/y `
=> `(u')/(1-2) +(1/x) u =x `so this linear equation is of the form
`u' + pu=q`
`p=-(1/x) , q=-x`
so I.F (integrating factor )
= `e^(int p dx) = e^(int -(1/x) dx) = e^(-lnx)=1/x`
and the general solution is given as
`u (I.F)=int q * (I.F) dx +c `
=>`u (1/x)=int (-x) * (1/x) dx +c `
=>`u (1/x)=int (-1) dx +c `
=>`u (1/x)= -x+c `
=>`u= (c-x)/(1/x) = x(c-x)`
but `u=1/y`
`1/y = x(c-x)`
`y=1/(x(c-x))`
is the general solution.
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