00:01
Okay, so for this question, we are given two curves, f and g.
00:07
And they're considered like x as a function of time for f and y as a function of time for g.
00:14
So they give us parametric equations for some curve.
00:17
And we're asked to figure out what this curve is.
00:21
So the way i think you should do this, and there are two ways, roughly, to go about this.
00:27
One way is to try and find formulas.
00:31
For fmg and then do the isolate substitute procedure we learned in the exercise at the start of this chapter.
00:41
The way i find is more successful in sort of all cases is to find a couple of points on the curve and then fill it in using common sense.
00:54
So let's start.
00:57
So there's like five points we can like clearly identify or try to.
01:04
To identify.
01:06
So they are, oh, sorry, like t equals minus two.
01:17
So x equals four.
01:20
And based on the rest of the graph, you'd guess like y equals minus nine.
01:27
So similar to t equals minus one.
01:29
You can actually read this one on completely.
01:33
So you get x equals one.
01:36
So i'll just, so t, x and here we get t y so y equals minus four for t is zero we get x is zero y is minus one t is one x is one y is zero and finally t is two x is four y um is minus one so in this case this is very close to just finding a formula because what i'm really doing is i'm guessing that this guy is just x squared and this guy is like minus x minus 1 squared um and from these two you could do like the whole isolate substitute procedure but we also now have these five points that are going to be on our curve.
02:49
So from there, let's try to draw this guy.
02:58
And since we see that x is all positive, let's give ourselves some more room to the right of the y -axis.
03:09
Okay, so x and y.
03:12
So t equals minus two.
03:14
X is four.
03:15
Y is minus nine...