00:01
I know with some people, they'll just memorize formulas.
00:03
I'm not a fan of memorizing things.
00:06
The reference angle, what i just tell students, it's the acute angle that's made with the x -axis.
00:20
So why is that important? well, the acute angle means that it's between zero degrees.
00:27
I guess it could be exactly zero degrees.
00:30
I like to write theta prime and then smaller than 90 degrees.
00:35
So if you look at part a, and instead of memorizing the formula, just think about, okay, well, 175 degrees would be over here, not quite into, i guess, we're in quadrant 2 would be the best way of doing it.
00:52
So the answer is going to be this angle right here, acute angle made with the x -axis, and so the thought process is to do 180 minus 175, and the reference angle would be 5 degrees.
01:06
So moving on to letter b, this time we're at 310 degrees.
01:13
And so my way of thinking is that we're getting into the fourth quadrant.
01:18
And so the angle that we're interested in is the acute angle made with the x -axis.
01:23
So again, i like to write theta prime right there...