00:01
Okay, so for this, it says that the sign of a plus the cosine of b are equal.
00:07
So sign of a is equal to the cosine of b.
00:09
And a is 4k minus 22, and b is 6k minus 13.
00:16
Well, here's the thing.
00:17
We know that if we have a sign of a is equal to the cosine of a, we know that, or the cosine of b, we know that the angle of a plus the angle of b, has to equal 90 degrees.
00:32
And that's just a trick identity, because if we have something like this, and let's just say this is like 30, and this is 60, well, if we have the sign of 1, and that's equal to the cosine of the other, so let's just call this angle 1 and angle 2.
00:49
So sign of angle 1 is going to be x over y.
00:53
Sign of angle 1 is x over y...