Ques. 1JEE Main 2025, 23 January (Evening Shift)
Let x=x(y) be the solution of the differential equation y= (x-y dxdy ) ( xy ), y>0 and x(1)= 2. Then (x(2)) is equal to :
- 2 ( e 2 )-1
- 1-2 ( e 2 )2
- 1-2 ( e 2 )
- 2 ( e 2 )2-1
Answer
(4) 2 ( e 2 )2-1
Solution
y dy=(x dy-y dx) xy
dyy=- xy d(x/y) (as x dy-y dx=-y2 d(x/y))
Integrate: y= xy+C; x(1)= 2 C=0
At y=2: x(2)2= 2
x(2)=2 2 x(2)2-1=2( 2)2-1
Answer: (4)