MHT CET202121 Sep 2021Evening ShiftMathematicsDifferential EquationsActual
The general solution of the differential equation. ( y x ) ( y x ) d x- [ ( x y ) ( y x )+ ( y x ) ] d y=0 is
Options
- Ay ^2 ( y x )= k
- Bx ( y x )= k
- C( y x )= k
- Dy ( y x )=k
Correct answer
D. y ( y x )=k
Step-by-step solution
We have ( y x ) ( y x ) d x- [ ( x y ) ( y x )+ ( y x ) ] d y=0 d y d x = ( y x ) ( y x ) ( x y ) ( y x )+ ( y x ) Put y x =v y=v x d y d x =v+x d v d x aligned & v + x dv dx = v v 1 v v + v = v ^2 v v + v v x dy dx = - v v v + v v & v + v v v v dv = - dx x 1 v dv + v d v =- dx x & | v |+ |+ x |=- | x |+ k |( v )( v )( x )| & = k aligned y ( y x )=k