00:01
Alright, so we've been given this trigonometric sine function, and we're told that we want to find when this guy is equal to zero on the interval between zero and 0 .005.
00:17
Alright, so we're just going to go ahead and start hacking away at this.
00:22
In order to solve this equation, we need to have the sine function part by itself, so let's divide both sides by 0 .008.
00:30
When we do that, we get 0 equals the sine of 2 pi times 254 .17 t plus pi over 6, and then we need to use the arc sine on both sides.
00:49
We need to ask ourselves, when is sine going to equal zero? when is sine going to equal zero? well, that comes from our unit circle.
00:59
On our unit circle, not the best circle, we have these key points, which is the point 10, 01, negative 10, and 0, negative 1.
01:14
And we need to remember that the cosine value is x, but the y value is sine.
01:20
So these values that we have highlighted in yellow there are the sine values.
01:24
So what angles will give us a sine value of zero? well, that's going to be zero radians and pi radians.
01:32
So we have zero or pi are going to be equal to 2 pi times 254 .17 t plus pi over 6.
01:46
So we're going to set this into two different equations.
01:49
We have zero equals all of this, and we're going to solve it.
01:59
But we also have pi equals all of that, and we're going to solve it.
02:07
So we're solving this separately now.
02:12
We have to subtract pi over 6 from both sides...