An object is launched from certain height into the air. The height is modeled by the the function h(t) = -4.8t^2+23t+20. The time (t) is measured in seconds.

A) What is the maximum height?
B) After how many seconds will it hit the ground?
C) From what height (initial height) was the object launched?
D) determine the domain for the above scenario?

4 answers

recall that the vertex (maximum height) of at^2+bt+c is at t = -b/2a

it hits the ground when h=0, so just solve the quadratic as usual.

h(0) = 20

while the function has domain (-∞,+∞), we have not yet achieved time travel, so in the real world, the domain is [0,∞)

Going back in time, when h=0, that would be how long ago a missile would have to be fired from ground level to achieve the same flight path.
A) I have the maximum height 47.55 or 47.6

B) I have 5.5 seconds that it will hit the ground

Are these correct? Thanks
10.1 therom
Lilly, you are correct.

"therom," you are out of order.