Let y = y x be the solution of the differential equation, 2 + sin x y + 1 . d y d x = − cos x , y &#62…

Let y=yx be the solution of the differential equation, 2+sinxy+1.dydx=cosxy>0, y0=1. If yπ=a and dydx at x=π is b, then the ordered pair a, b is equal to
  1. 2,32
  2. 1,1
  3. 1, 1
  4. 2, 1

Solution

dy1+y=-cosx2+sinxdx

ln1+y=-ln2+sinx+lnc

1+y2+sinx=c

We know y0=1

Soc=4

1+y=42+sinx    y=42+sinx-1

yπ=2-1=1=a

dydx=-42+sinx2·cosx=1

At  x=πb=1

a,b=1,1

Asked in: JEE Main 2020 (02 Sep Shift 1)

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