AP EAMCET2005MathematicsDifferential Equations
Observe the following statements I. If d y+2 x y d x=2 e^ -x^2 d x , then y e^ x^2 =2 x+c II. If y e^ -x^2 -2 x=c , then d x= (2 e^ -x^2 -2 x y ) d y which of the following is a correct statement?
Options
- ABoth I and II are true
- BNeither I nor II is true
- CI is false, but II is true
- DI is false, II is true
Correct answer
C. I is false, but II is true
Step-by-step solution
I. d y+2 x y d x=2 e^ -x^2 d x d y d x +2 x y=2 e^ -x^2 This is a linear differential equation in y Here, P=2 x, Q=2 e^ -x^2 I.F. =e^ P d x =e^ 2 x d x =e^ x^2 Complete solution is aligned & y e^ x^2 =2 e^ -x^2 e^ x^2 d x+c y e^ x^2 & =2 x+c aligned II. y e^ x^2 -2 x=c On differentiating w.r.t x , we get y e^ x^2 2 x+e^ x^2 d y d x -2=0 aligned & e^ x^2 d y d x & =2-2 x y e^ x^2 & d y d x & =2 e^ -x^2 -2 x y aligned I is true and II is false.