00:01
So before we actually do a, i would make note that it would probably be better to do b first and then just use the result from b to plug in a.
00:13
But the way they have it set up, they want us to do this first and then to go from there.
00:17
So i'm just going to go ahead and follow the steps.
00:20
But if you want, you can just kind of skip ahead, see what we do in b, and then just plug one into that value.
00:26
And that should give you the same thing to get over here.
00:28
I mean, it'll save you a lot of time, but just kind of for sake of how they have the problem set up.
00:32
I'm going to kind of go from a, then b.
00:36
So over here, remember that the velocity, if we think about it, is just the derivative of our position.
00:44
So in this case, h prime of t is going to be equal to v of t.
00:52
And we know, and maybe i should write out what the definition of this is first.
00:59
So h prime of t is going to be equal to the limit as h approaches 0 of h of t plus h minus h of t all over h.
01:18
And so in this case if we want one, then we're just going to replace those t's with ones.
01:25
So since this is the same thing as v of t, we could just go in and write that.
01:29
So it would be v of 1 is equal to.
01:31
The limit as h approaches 0 of capital h of 1 plus little h minus h of 1 all over little h.
01:46
And now we can plug in 1 plus h into here as well as 1.
01:51
So that would be the limit as h approaches 0.
01:55
So h of 1 plus h, so that would be 10 times 1 plus h.
02:02
And then minus 1 .86, 1 plus h squared, minus.
02:08
Well, if we come over here and plug in 1, so that would be 10 minus 1 .86.
02:14
And then this is all over h.
02:17
Actually, i'll need to scoot this down a bit more, it looks like.
02:25
Then we can go ahead and distribute everything.
02:29
So this would just be 10 plus 10h.
02:34
This here is going to be, well, if we expand that out, it would first be 1 plus 2h plus h squared, and then we would distribute the negative 1 .86.
02:44
So i'll go ahead and do that.
02:47
And actually, before we do that, notice first, this 10 and that 10 cancel out with each other, and then if we distribute this negative 8 .6, this one and this will cancel out because we'd have negative there.
03:01
So those cancel out.
03:03
So actually, let's write that out just so you can see what we have left before i actually start doing stuff.
03:09
So it would be 10h minus 1 .86 times 2h plus h squared all over h.
03:18
And then we can go ahead and simplify this down by combining our like terms.
03:25
So we'd have 10 minus.
03:30
Actually, let me distribute that 1 .86, so 1 .86 times 2.
03:35
So this is going to be minus 3 .72, and then minus 1 .86 squared.
03:45
There should be an h there.
03:46
Then we can combine those, so 10 minus that would be 6 .28.
03:51
So we have the limit as h approach to 0 of 6 .28h minus 1 .86h squared all over h.
04:02
And now notice, we can divide this h into each of those terms to just give, the limit as h approaches 0 .0 .6 .28 minus 1 .86h.
04:16
And then lastly, we can go ahead and apply our limit.
04:19
That's just going to turn this term to zero, and we're going to be left with 6 .28.
04:25
And actually, what are the units with this? meters per second.
04:29
So this would be meters per second.
04:31
So our velocity, after one second, is going to be 6 .28 meters.
04:37
Per second.
04:39
Now we can come over here and repeat all these same steps, but in general.
04:49
So instead of replacing t with 1, we're just going to replace it with a.
04:55
So let me just go ahead and erase this here.
05:01
So this should be the limit as h approaches 0 of capital h of a plus little h minus capital.
05:10
H of little a, all over a little h...