JEE Main202131 Aug 2021Morning ShiftMathematicsDifferential EquationsActual
If d y d x = 2 x + y - 2 x 2 y , y 0 = 1 , then y ( 1 ) is equal to :
Options
- Alog 2 1 + e 2
- Blog 2 ( 2 e )
- Clog 2 ( 2 + e )
- Dlog 2 ( 1 + e )
Correct answer
D. log 2 ( 1 + e )
Step-by-step solution
Given that d y d x = 2 x + y - 2 x 2 y = 2 x 2 y - 1 2 y ⇒ 2 y 2 y - 1 d y   =   2 x d x By using Variable Separable method ∫ 2 y d y 2 y - 1 = ∫ 2 x d x Let 2 y - 1 = t ⇒ 2 y ln 2 d y = d t ∫ d t t 1 ℓ n 2 = ∫ 2 x d x We know that ∫ 1 x d x   =   ln x   +   c   &   ∫ a x d x   =   a x ln a + c . ⇒ ln t ln 2 = 2 x ln 2 + c ln 2 ⇒ ln t = 2 x + c ⇒ ln 2 y - 1 = 2 x + c when x = 0 ,   y =