0
1.3kviews
Solve $(1+y^2)dx+(x-e^{tan^{-1}y})dy=0$ .
1 Answer
written 6.2 years ago by | • modified 6.1 years ago |
Since the degree of the dependent variable x is one it has to be reduced to the form
$ \frac{dx}{dy}+Px=Q$
Dividing throughout by $(1+y^2)$ we get,
$\frac{dx}{dy}+\frac{x}{1+y^2}=\frac{e^{\tan^{-1}y}}{1+y^2} $
$ P=\frac{1}{(1+y^2)}$ and $Q=\frac{e^{\tan^{-1}y}}{1+y^2}$
$I.F=e^{\int P dy}$
$= e^{\int \frac{1}{(1+y^2)}dy}$
$ =e^{\tan^{-1}y}$
The solution is
$xe^{\tan^{-1}y}=\int \frac{e^{\tan^{-1}y}}{(1+y^2)}e^{\tan^{-1}y}dy+c $
For integrating on R.H.S
$Put\ \tan^{-1}y=t$
$\frac{1}{(1+y^2)}dy=dt$
$xe^{\tan^{-1}y}=\int e^{2t}dt+c$
$xe^{\tan^{-1}y}=\frac{1}{2} e^{2\tan^{-1}y}dt+c $