I have obtained following integrating factor from ODE ($y^{\prime} + a(x) = g(x)$):
$ e^{\,A(x)} \:\:=\:\ e^{- \ln |\cos(x)|+c}$
where $ e^{\,A(x)}$ is integrating factor and $A(x) = \int a(x)\,\mathrm{d}x$.
$e^{- \ln |\cos(x)|+c}$ should equal to $ \:\frac{1}{\cos x}\:$.
How do I simplify the equation to $ \:\frac{1}{\cos x}\:$?
Thanks.
Use that $$-\log(\cos(x))=\log\frac{1}{\cos(x)}$$