First we are going to find the common denominator of both fractions. To do that, we are going to multiply their denominators:
[tex](1+sin \alpha )(1-sin \alpha )=1-sin^2 \alpha [/tex]
Now we can rewrite our expression using the common denominator:
[tex]\frac{1-sin \alpha }{1-sin^2 \alpha } + \frac{1+sin \alpha }{1-sin^2 \alpha} = \frac{2}{1-sin^2 \alpha} [/tex]
Finally, we can use the trig identities: [tex]1-sin^2 \alpha =cos^2 \alpha [/tex] and [tex]sec \alpha = \frac{1}{cos \alpha } [/tex] to simplify our trig expression:
[tex]\frac{2}{cos^2\alpha}=2sec^2 \alpha [/tex]
We can conclude that the correct answer is the fourth one.
