Final answer:
The patrol function focuses on proactive prevention and routine monitoring of communities, while the investigation function deals with reactive response and delves into specific incidents or crimes, aiming at solving crimes through evidence collection and analysis.
Step-by-step explanation:
The patrol function and the investigation function in policing serve different purposes. The patrol function focuses on proactive prevention by involving routine monitoring of communities and emphasizing visibility and deterrence. On the other hand, the investigation function deals with reactive response by delving into specific incidents or crimes, aiming at solving crimes through evidence collection and analysis.