Question

Integrating factor of $\frac{dy}{dx}+y\sec x=\tan x$ is:

• A. $\sec x$
• B. $\tan x$
• C. $\sec x+\tan x$
• D. $\cos x$

Answer 1

Answer: (C)

$\sec x+\tan x$

$\frac{dy}{dx}+y\sec x=\tan x$
$I.F=e^{\int P\left(x\right)dx}$
$=e^{\int \sec xdx}$
$=e^{log|\sec x+\tan x|}$
$\Rightarrow I.F=\sec x+\tan x$