We need to determine the biggest value among cos1, cos2, and cos3
Since 1 is in the first quadrant, then the cosine is positive, then cos1? 0
However, 2 belongs to the interval (pi/2, pi) =(3.14/2, 3.14)which is in the 2nd quadrant where the cosine is negative ,
Also, 3 belongs to the interval (pi/2, pi) where cosine is negative.
Then cos1 is the biggest value.
Because 1 is in the interval (0,pi/2), namely the first quadrant, where the function cosine is positive, then cos 1 > 0.
Because 2 and 3 are in the interval (pi/2, pi), then cos2 and cos 3 < 0, because of the fact that the interval (pi/2, pi) is the second quadrant, where the values of cosine function are negative.
So the biggest element is cos 1.
The calculus have been made using the approximate value of pi=3.1416...
To find the biggest among cos1 cos2 and cos 3.
cos1 is a ratio of the first quadrant and it is is positive.
cos2 is a ratio in secon quadrant an so it is negative. So cos 2 < cos1.
Cos 3 is also in 2rd quadrant, as 3 < Pi. So it is negative
Cosine is decreasing function in the 2nd quadrant from 0 to -1. So cos3 < cos2.
Thus cos3 <cos2 < cos1