2.To make actions,to tell that you've a particular quality.
3.To make actions to show that how to do something.
4.To take part in a protest or an event that is supporting something.
2.He was trynna show that he could dance good by dancing in front of me in the club.
3.You ain't doing it rightly,let me demonstrate or let me give a demo.
4.We're gonna demonstrate in tomorow's protest!!!!