MHT CET202020 Oct 2020Evening ShiftMathematicsDifferential EquationsActual
The solution of the differential equation x ( y x ) d y= [y ( y x )-x ] d x is
Options
- A( x y )= |x|+c
- B( y x )= |y|+c
- C( y x )= |x|+c
- D( x y )= |y|+c
Correct answer
C. ( y x )= |x|+c
Step-by-step solution
We have x ( y x ) d y= [y ( y x )-x ] d x d y d x = y ( y x )-x x ( y x ) = ( y x )- 1 ( y x ) d y d x - ( 1 x ) y=- cosec ( y x ) Put y x =v y=v x d y d x =v+x d v d x ( v + xdv dx )- v =- cosec v x dv dx =- cosec v dv cosec v =- d x x v dv =- | x |- v=- |x|+c₁ x+c= v ( y x )= |x|+c