Let y = y ( x ) be the solution of the differential equation d y d x = 1 + x e y - x ,   - 2 < x…

Let y=y(x) be the solution of the differential equation dydx=1+xey-x, -2<x<2, y0=0, then the minimum value of yx, x-2,2 is equal to :
  1. 2-3-loge2
  2. 2+3+loge2
  3. 1+3-loge3-1
  4. 1-3-loge3-1

Solution

Given,

dydx=1+xey-x

dy-dxey-x=xdx

dy-xey-x=xdx

-ex-y=x22+c

At x=0,y=0c=-1

So, the particular solution is 

ex-y=2-x22

y=x-ln2-x22

dydx=1+2x2-x2=2+2x-x22-x2

dydx=x2-2x-2x2-2

dydx=x2-2x-2x+2x-2

If dydx=0x2-2x-2=0

x=2±122

x=1±3

So minimum value occurs at x=1-3

y1-3=1-3-ln2-(4-23)2

=1-3-ln3-1

Asked in: JEE Main 2021 (25 Jul Shift 1)

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