Let y = y x be the solution curve of the differential equation d y d x + 2 x 2 + 11 x + 13 x 3 + 6 x 2 + 11…

Let y=yx be the solution curve of the differential equation dydx+2x2+11x+13x3+6x2+11x+6y=x+3x+1,x>-1, which passes through the point 0,1. Then y1 is equal to
  1. 12
  2. 32
  3. 52
  4. 72

Solution

Given,

dydx+2x2+11x+13x3+6x2+11x+6y=x+3x+1

Now comparing with dydx+y×px=qx
We get px=2x2+11x+13x3+6x2+11x+6

So IF=e2x2+11x+13x3+6x2+11x+6dx

Now finding the integration we get,

pxdx=2x2+11x+13dxx+1x+2x+3

Using partial fraction we get,

2x2+11x+13x+1x+2x+3=Ax+1+Bx+2+Cx+3

On solving we get A=42=2B=1 and C=-1

So, pxdx=Alnx+1+Blnx+2+clnx+3

=lnx+12x+2x+3

So, IF=epxdx=x+12x+2x+3

Now solution of differential equation is given by

 y×IF=Q×IFdx

y×x+12x+2x+3=x+3x+1x+12x+2x+3dx

y×x+12x+2x+3=x33+3x22+2x+c

Now given curve passes through 0,1,

So, 1×0+120+20+3=033+3×022+2×0+cc=23

So, curve becomes y×x+12x+2x+3=x33+3x22+2x+23

Now put x=1 we get, y×1+121+21+3=133+3×122+2×1+23

y×3=1+32+2y×3=92

 y1=32

Asked in: JEE Main 2022 (29 Jul Shift 2)

Practice more Differential Equations questions on Aicharya