JEE Main20204 Sep 2020Evening ShiftMathematicsDifferential EquationsActual
The solution of the differential equation d y d x - y + 3 x log e ( y + 3 x ) + 3 = 0 is (where C is a constant of integration)
Options
- Ax - 1 2 log e ( y + 3 x ) 2 = C
- Bx - log e ( y + 3 x ) = C
- Cy + 3 x - 1 2 log e x 2 = C
- Dx - 2 log e ( y + 3 x ) = C
Correct answer
A. x - 1 2 log e ( y + 3 x ) 2 = C
Step-by-step solution
   d y d x - y + 3 x ln ( y + 3 x ) + 3 = 0 d y d x + 3 = y + 3 x ln ( y + 3 x ) d d x ( y + 3 x ) = y + 3 x ln ( y + 3 x ) ∫ ln ( y + 3 x ) ( y + 3 x ) d ( y + 3 x ) = ∫ d x Let ln ( y + 3 x ) = t 1 ( y + 3 x ) d ( y + 3 x ) = d t ∫ tdt = ∫ dx t 2 2 = x + c ( ln ( y + 3 x ) ) 2 2 = x + c