The integrating factor of equationa)b)c)d)Correct answer is option 'A'...
Concept:
The standard form of a first-order linear differential equation is,

Where P and Q are the functions of x.
Integrating factor, IF = e∫Pdx
Now, the solution for the above differential equation is,
y(IF) = ∫IF.Qdx + C
Where P and Q are the functions of y.
Integrating factor, IF = e∫Pdy
Now, the solution for the above differential equation is,
x(IF) = ∫IF.Qdy + C
Calculation:
Given the differential equation is
Put tan y = t
By differentiating with respect to t,
⇒ sec2 y dy = dt
Now, the given equation becomes

Now, it is in the form of a first order linear differential equation.
Integrating factor
