Let y=y(x) be the solution curve of the differential equation (1+ x) dydx+(y+1) x=0, y(0)=0. If the curve y=y(x) passes through the point ( , -12 ), then a value of is :
- 6
- 4
- 3
- 2
Answer
(4) 2
Solution
(1+ x) dydx+(y+1) x= ddx [(1+ x)(y+1) ]=0
(1+ x)(y+1)=C
y(0)=0 (1)(1)=C C=1
Point ( ,- 12 ): (1+ ) 12=1
=1 = 2 (one value)
Answer: (4)