Let y = y ( x ) be the solution of the differential equation cos x d y d x + 2 y sin x = sin 2 x , x ∈…

Let y=y(x) be the solution of the differential equation cosxdydx+2ysinx=sin2x,x0,π2
If y(π/3)=0, then y(π/4) is equal to :
  1. 2-2
  2. 2+2
  3. 2-2
  4. 12-1

Solution

dydx+2tanx·y=2sinx

I.F. =e2tanxdx=sec2x

solution is
y·sec2x=2sinx·sec2xdx+C

ysec2x=2secx+C
0=2.2+CC=-4
ysec2x=2secx-4
yπ4=2-2

Asked in: JEE Main 2020 (05 Sep Shift 2)

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