00:01
So first of all, make sure that you are in degree mode.
00:06
And so when you're trying to solve sine of 2x is equal to 0 .5, i don't think you need to, because it is a point on the unit circle, that what you would do first is the inverse sign to move it over.
00:27
And it is exactly 30 degrees.
00:32
And if i go back to some of the problems here, they have a lot of correct answers.
00:40
The reason why you have so many correct answers is because you have to divide by two.
00:47
So one correct answer for that very first option is 15 degrees, but then you can also think about on the unit circle that, okay, so if right here is one half, well over here at 150 degrees so 2x could also equal 150 degrees if you divide both sides by 2 you get 75 degrees well i guess i should circle that in green there you go but i think there's only two correct answers on that one i don't know why there's two more because they only want answers between negative 180 degrees hmm well i'll have how about this? what if i went a full, okay, what if i went, yeah, that makes sense.
01:55
What if i went negative, let's see, 180 plus another 30, so it would be negative 210.
02:03
So if i divide both sides by two, negative 210, divided by two, it would be negative 105 degrees.
02:13
I don't know why i didn't think about that.
02:14
But then also a full revolution clockwise, but then backwards, that would be 2x is equal to negative 330 because it's that 30 degree angle.
02:29
So negative 330 divided by 2 is negative 165.
02:35
So that's a lot of work for just the first answer, first four blinks.
02:41
So as i move on to the next one, again, you want to start with doing the inverse cosine of negative 0 .6.
02:57
And again, we have 2x equals that.
03:07
So second cosine, negative 0 .6.
03:12
And i get an answer of, and we want to round to the nearest degree.
03:20
So as i typed that in, i got 2x is equal to 127 degrees.
03:26
So think about on the unit circle that that's over here, 27 degrees, but i could have also gone, let's see, what i could have done is a clockwise, so if i did 360 minus 270, sorry, i said that wrong, 360 minus 127, i get negative 233 degrees, but i could have also done this way, just this angle, so that would be positive, 233 degrees as well as negative 127 degrees but what i still need to do is divide all these answers by two so let me take that 127 divided by two and when you actually round that you i'm gonna write it because it was a hundred twenty six point nine when you divide that by two you get 63 degrees that's the answer i'm to commit to negative 63 degrees as well so if i did that 120 and divide that 233 by 2, i get 117 degrees, as well as negative 117 degrees.
05:02
The next one's actually a little bit easier because you can see there's only one correct answer.
05:07
So let me look at that tangent of x over 3.
05:15
So you have to type in inverse tangent...