Simplify the integrand
[tex]\dfrac{1-\sin^2(t)}{\sin^2(t)} = \dfrac{\cos^2(t)}{\sin^2(t)} = \cot^2(t)[/tex]
Recall the derivative of csc(t),
[tex]\dfrac d{dt} \csc(t) = -\cot^2(t)[/tex]
It follows that
[tex]\displaystyle \int \frac{1-\sin^2(t)}{\sin^2(t)} \, dt = \int \cot^2(t) \, dt = \boxed{-\csc(t) + C}[/tex]
