00:01
And this problem, we're given this diagram.
00:03
And if you go back to the previous section, they're using the same information, but they're finding a different part.
00:10
So just so we know what this is, we are looking at the distance of a rotating beacon.
00:17
The rotating beacon is located at point a next to a long wall.
00:21
The beacon is four meters from the wall.
00:24
The distance, so we are determining the distance a.
00:27
And it's given by this equation.
00:32
And in this one, we are finding it at time 1 .24.
00:37
Because our calculators do not have a secant button, we have to use the identity.
00:43
A equals four times the absolute value.
00:46
Instead of secant, it's going to be cosine of x, or one over, sorry, the cosine of x...