Q40 / 90 · JEE Main 2022 (26 Jun Shift 2) · Mathematics

If dydx+exx2−2y=x2−2xx2−2e2x and y0=0, then the value of y2 is

  • A
    -1
  • B
    1
  • Correct answer
    C
    0
  • D
    e

Solution

Given

dydx+exx2−2y=x2−2xx2−2e2x

It is linear differential equation so,

IF=e∫x2-2exdx

=ex2ex-2∫xexdx-2ex  =ex2ex-2xex-ex-2ex

IF=ex2-2xex

Now solution is given by

y×ex2-2xex=∫ex2-2xex×x2-2xx2-2e2x

=∫ex2-2xex×x2-2xexx2-2ex

Now let  x2-2xex=t

We get exx2-2x+ex2x-2dx=dt

exx2-2x+2x-2dx=dt 

exx2-2dx=dt

y×ex2-2xex=∫et×t×dt

y×ex2-2xex=ett-1+c

y×ex2-2xex=ex2-2xexx2-2xex-1+c

Now at x=0  y=0

0×e0=e00xex-1+c

0=-1+c  c=1

Putting the value of c=1 we get the equation as

⇒y×ex2-2xex=ex2-2xexx2-2xex-1+1

Now putting x=2 in equation we get

y×e4-4e2=e4-4e24-4e2-1+1

⇒y×e0=e00e2-1+1

⇒y=-1+1=0

Hence, the correct answer is option: 'C'.

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