The algebra symbol f(n) means what?

What is the probability of rolling a single die greater than 4

Ihave trouble finding the nth term of a linear sequence

Astuntman jumping off a 20-m-high building is modeled by the equation h=20-5t^2, where t is the same in seconds. a high-speed camera is ready to film him between 15m and 10m above the ground. for which interval of time should the camera film him?