00:01
So we're given a mass hanging from a spring set in motion, and we're given the velocity with the positive direction being upward.
00:07
We want to determine the position function.
00:09
So that's going to be s of t is going to be the antiderivative of v of t with respect to t.
00:19
So that ends up giving us the antiderivative of that cosine function.
00:26
So it'll be 2 negative 2 sine pi t.
00:36
Because then if we took the derivative of this, actually it's going to be just 2 sine pi t.
00:45
Because if we took the derivative of this, we would end up getting 2 times cosine of pi t times pi using the chain rule.
00:58
So we see that that would actually be what we end up with.
01:01
So this right here would be our position function.
01:05
And then we just checked that.
01:07
So then we're held plus c.
01:09
Well, if we know that s of 0 is equal to 0, then s of 0 in this case is going to be 0 plus c...