sqrt(cos a+1)/(1-cos a)
I did (not sure how to format the final answer but the numerator should be sqrt'd. $$\sqrt{\frac{{\cos a +1}}{1-\cos a}}=\sqrt{\frac{{\cos a +1}}{1-\cos a}\frac{{\cos a +1}}{1+\cos a}}=\left|\frac{1+\cos a}{\sin a}\right|$$ Thanks to gimusi for formatting.
Is that correct?