Answer
Proven below.
Work Step by Step
The identity says: $tan(\theta)=\frac{sin\theta}{cos\theta}$ and $sec(\theta)=\frac{1}{cos(\theta)}$. Hence $sin(\theta)\cdot sec(\theta)=sin(\theta)\cdot \frac{1}{cos(\theta)}=\frac{sin(\theta)}{cos(\theta)}=tan\theta.$
