Question

The integrating factor of linear differential equation `dy/dx+ysecx=tanx` is

(a)secx- tan x

(b) sec x · tan x

(c)sex+tanx

(d) secx.cotx

Answer 1

`dy/dx+P.y=Q`

therefore P=secx

`I.f=e^(intsecxdx)=e^(log|sex+tanx|)`

=secx+tanx