00:01
Evaluate each of the following.
00:02
The first thing i want to do is make sure we know what quadrant we're looking in for each one of those.
00:06
So the first one here, i see if we're looking at quadrant three, that's going to be about right there.
00:12
So we have a reference angle of pi over four.
00:15
So this is going to be the same as negative sign of pi over four.
00:22
And i know the sign of pi over four is the square root of two over two.
00:27
When we're looking at the next one, cosine of negative 5 pi over 6, 5 pi over 6 is going to be about right here, which means its positive angle is going to be here.
00:39
So we're looking in quadrant 3, cosine is negative in quadrant 3, so it's going to be the negative cosine of 7 pi over 6.
00:48
Well, that has a reference angle of pi over 6, so to be negative cosine a pi over 6, which is going to be negative, and that's square root of 3.
00:58
Over 2, cosine of pi over 6, square to 3 over 2.
01:03
We're going to look at this one, i'm going to reduce this to pi over 6.
01:07
So, pi over 6 is going to be in that first quadrant.
01:11
So we need to see what is the tangent of pi over 6.
01:14
Well, that's going to be 1 over the square root of 3, which is the same thing as square to 3 over 3.
01:21
Seekin of negative 7 pi over 4...