HI, I need to understand about the Arithmetic Sequence Formula. There are tons of instructions on the Internet but I still can't understand this formula. Can someone please help me explain? I want an explanation about the whole formula. eg: Why is it n-1?

Aman steps out of a plane at a height of 4,000m above the ground falls 2,000m very quickly and then opens his parachute and slowly falls the remaining 2000m to the ground what height above the ground would be the best choice for a reference point

The table below shows the approximate height of an object x seconds after the object was dropped. the function h(x)= -16x^2 +100 models the data in the table. for which value of x would this model make it the least sense to use? a. -2.75 b. 0.25 c. 1.75 d. 2.25

Acd that is originally priced at $15.85 red-tagged for the sale. what is the sale price of the cd