00:01
For this problem, we're told that the arc of a baseball, it's given by the equation y equals negative 3 over 4 ,000 x squared plus 3 over 10x plus 3, where x is the distance from the home plate.
00:13
We want to find the max value, and we want to answer whether or not the ball will clear a fence, which is 8 feet tall at a distance of 385 feet.
00:23
Essentially, is y of 385 greater than 8? so, to figure out the max value, we want to find the vertex.
00:31
Can find the vertex by first figuring out what the x value of the vertex is going to be, which in this form it's going to be given by negative b over 2a.
00:41
B is 3 over 10, so we'll have negative 3 over 10, divided by, or we can do this as negative 3 over 10 times the reciprocal of our a.
00:51
So we have negative 3 over 10 times 4 ,000 over 3.
00:59
Or in fact, negative 4 ,000 over 3, so we'd have double negative.
01:03
The threes will multiply each other out.
01:08
We'd have 4 ,000 over 10.
01:10
When we divide by 10, we can take off a 0, so that's going to be 400...