Answer:
C
Step-by-step explanation:
Firstly, we will identify the angle that has the given cosine value
From what we can see, the arc cos of this value is 45 degrees
but, as we can see, the value is negative
On the quadrants, the value of cosine is negative on the 2nd and 3rd quadrant
2nd quadrant ranges from 90 - 180
That is pi/2 to pi
3rd ranges from 180 to 270
That is pi to 3pi/2
Kindly recall, we are considering angles from -360 to 360
So what this mean is that we will consider angles that are negative of what we have as positive angles on the first and fourth quadrant on which cosine is positive
Thus, we have the following;
5pi/4 is same as 225 degrees
This is on the 3rd quadrant, and cosine is negative there
7pi/4 is same as 315 and this is on the fourth quadrant
This is expected to be negative because normally, cosine is positive on that axis and what we have should be negative
3pi/4 is same as 135
This is on the second quadrant and normally, cosine is negative here so we do not need to negate the angle measure
pi/4 is on the first quadrant and cosine is positive here;
Since the value we have here is positive, we have to negate the angle measure
So the correct angles are;
negative pi/4
positive 3pi/4
positive 5pi/4
negative 7pi/4
