00:01
So for this question, we are given parametric equations.
00:07
So x is n t and y equals 3e to the minus t over 2.
00:20
And we don't know what the domain of t is, but we are asked to identify the graph of this barometric equation along a set of other ones.
00:33
So here we have all the graphs in order and we're asking which one is it.
00:40
So to do that, we are going to look at this and just start to identify some things.
00:46
So x is an ln of t.
00:52
So if t is just allowed to be any positive number, x is going to be any number.
00:59
So we'd expect the graph to extend infinitely in the x directions.
01:08
Looking at the y one, we expect, well, y is a positive function.
01:16
So whatever graph it is, we know y is bigger than a equal to 0.
01:25
In fact, it's actually just straight up bigger than 0.
01:32
So why is bigger than 0? this is something we know.
01:37
And then it might be useful to just find some points.
01:40
So let's say like t equals 1.
01:48
So we'd find x equals 0 and y equals 3 times e to the minus 1⁄22.
01:59
Which is 3 divided by the square root of e.
02:07
Now, you shouldn't try to do this exactly.
02:11
The exact number doesn't even matter that much.
02:15
So e is 2 .7, it's pretty close to 3.
02:18
So this is going to be close to square root of 3, which is going to be something like, i don't know, it's going to be like 1 .6, 1 .7, something like this.
02:31
So let's say it's roughly 1 .6, maybe 1 .7.
02:35
Let's say 1 .7...