Answer:
[tex]\large\boxed{\theta=k\pi,\ k\in\mathbb{Z}}[/tex]
Step-by-step explanation:
[tex]\sec\thets\cdot\sin\theta=0\iff \sec\theta=0\ \vee\ \sin\theta=0\\\\\sec\theta\neq0\ \text{for any value of}\ \theta\\\\\sin\theta=0\Rightarrow\theta=k\pi\ \text{where}\ k\in\mathbb{Z}[/tex]
