00:01
T here gives us the height of a firework after t seconds, and they were initially, i guess, launched at a height of eight feet.
00:11
So what we want to figure out first in part a is we want to figure out what the maximum height is that these fireworks can actually get to.
00:19
So the maximum height is going to occur at the vertex.
00:23
So v is equal to negative b divided by 2a, comma, f of negative b divided by 2a, f of negative b divided by 2a, and the reason it's going to occur at the vertex is because we have this negative value for a.
00:36
So we're going to have a downward facing u shape for our parabola, which i can illustrate on this graph really quick.
00:43
So we just have a downward facing u shape on a parabola.
00:46
So the maximum height or the maximum y value is going to come at the vertex here.
00:51
So that's why we can find the vertex and that will give us the maximum height.
00:56
So negative b in this case would be negative 100 divided by negative 16.
01:00
Times 2, so v is equal to 100 divided by 32, comma, f of 100 divided by 32...