O valor do determinante da matriz

$A=\left(\begin{array}{ccc}\mathrm{sen}\left(\theta \right)& \cos \left(\theta \right)& \sec \left(\theta \right)\\ \cos \left(\theta \right)& \mathrm{sen}\left(\theta \right)& \mathrm{cossec}\left(\theta \right)\\ \mathrm{tg}\left(\theta \right)& 1& {\sec }^2\left(\theta \right)\end{array}\right)$, para $0<\theta <\frac{\pi }{2}$, é