00:01
Okay, so let's start by dividing both sides by 2.
00:04
So we can isolate this cosine.
00:10
Okay, so we can relate this as negative 1 over the square root of 2.
00:15
So when is cosine negative? well, looking at this, cosine is negative when our x -axis is negative.
00:23
So that's in quadrant 2 and quadrant 3.
00:26
So we have square root of 2 here and a negative 1.
00:32
So that means here is 1, a negative 1.
00:35
So that gives us, this is going to be a variation of pi over four.
00:42
For this, in quadrant two, this is pi minus pi over four.
00:47
So we get three pi over four.
00:51
And in quadrant three, we have pi plus pi over four.
00:55
So we get five pi over four.
01:05
Okay, so we see that theta, or actually data over two, is equal to three pi over four, plus our period for cosine, which is 2 pi, times some random integer n...