Q.

Let y=y(x) be the solution of the differential equation secxdydx-2y=2+3sinx,  x(-π2,π2), y(0)=-74.Then y(π6) is equal to:    [2026]

1 -52  
2 -54  
3 -33-7  
4 -32-7  

Ans.

(1)

dydx-2ycosx=2cosx+3sinxcosx

I.F.=e-2sinx

e-2sinxy=e-2sinx(3sinxcosx+2cosx)dx

y.e-2sinx=e-2sinx(-32sinx-74)+C

y=-32sinx-74+Ce2sinx

 y(0)=-74C=0

y(π6)=-32·12-74=-52