Q.

Let y = y(x) be the solution curve of the differential equation x(x2+ex)dy+(ex(x–2)y–x3)dx=0, x>0, passing through the point (1, 0). Then y(2) is equal to          [2025]

1 22–e2  
2 44+e2  
3 44–e2  
4 22+e2  

Ans.

(2)

We have, x(x2+ex)dy+(ex(x–2)y–x3)dx=0

⇒ x(x2+ex)dydx+ex(x–2)y=x3

⇒ dydx+ex(x–2)x(x2+ex)y=x3(x2+ex)x

Where, P=ex(x–2)x(x2+ex) and Q=x2(x2+ex)

I.F.=e∫ex(x–2)x(x2+ex)dx=e∫ex+2xex+x2dx–∫2xdx=eln|ex+x2|–2 ln x

I.F.=1+exx2

Now, y·(1+exx2)=∫x2x2+ex·x2+exx2dx+C

⇒ y(1+exx2)=x+C

It is passing through the point (1, 0), then

C = –1

So, y(1+exx2)=x–1

Then y(2)=44+e2