NTA Abhyas JEE Main2020MathematicsDifferential EquationsPractice
If y x is a solution of d y d x - x y 1 + x = 1 1 + x and y 0 = - 1 , then the value of y 2 is
Options
- A- 1 2
- B- 1 3
- C- 1 4
- D- 1 5
Correct answer
B. - 1 3
Step-by-step solution
I.F. = e - ∫ x 1 + x d x = e - ∫ x + 1 - 1 x + 1 d x = e - x + ln ⁡ x + 1 =   e - x · | ( x + 1 ) | y · x + 1 e – x = ∫ x + 1 x + 1 e - x d x + c y · | ( x + 1 ) | e – x = - |   x + 1   | x + 1 e - x + c ⇒   y = - 1 x + 1 + c e x |   x + 1   | x = 0 ,   y = - 1 ⇒   - 1 = - 1 + c ⇒   c = 0 ⇒       y = - 1 1 + x y 2 = - 1 3