00:01
So we want to find the value of c such that the area of the region bounded by the parabolas, these two parabolas that's listed here, is 576.
00:11
So the first thing we want to do is find the point of intersection between these two guys so that we can get a feel for what region we're actually looking at.
00:19
So in order to find the point of intersection, which i've labeled p -o -i, let's set y equal to y, or x squared minus c, squared equal to c squared minus x squared.
00:35
And then we do the quick algebra.
00:39
Add x squared to both sides, add c squared to both sides, so that we can just get the x's on one side and the constants on the other side.
00:49
So those cancel.
00:50
And we've got that x squared equals, in fact 2x squared equals 2 c squared.
00:58
The two is divide each other out.
01:00
And then we're solving for x.
01:03
So x is equal to plus or minus the square root of c squared, which is equal to plus or minus c.
01:11
And then plugging c back into either one of these functions, we can find the value for y, and we know that plugging in plus or minus c, will give us c squared minus c squared, which is y equals zero.
01:25
So the two points of intersections that we have, since we have two c values, are minus c for our x and zero for our y, and positive c for our x and zero for our y.
01:38
So those are our points of intersections.
01:43
So let's graph these parabolas over here so that we can get a feel for what we're actually looking at.
01:51
So roughly, the first guy is a parabola that is pointing upward and shifted down.
01:59
Downward by c square units.
02:02
So it is something like this and i'm not going to be super precise.
02:10
I just want a general feel for what i'm working with.
02:13
And then the next parabola, which i'm going to label as green, that is a downward pointing parabola shifted upward c square units.
02:22
So something like this.
02:28
And then we know that our points of intersection are at when y is theory.
02:34
We have negative c and positive c.
02:39
So this here is x equals negative c and this is x is positive c.
02:50
Okay, so we want to find the region that is enclosed between the blue and green curve.
02:57
We want to make that area 576 and we want to find the c values that ensure that this whole region is 576...