Pretty sure it’s irrational
Answer:
(2pi)/5
Step-by-step explanation:
The cosine function cos(x) has a period of 2*pi.
If we change the argument of the cosine, the new argument will have a period of 2*pi. If the new argument is 5x, we have that the period will be:
5x = 2*pi
x = 2*pi/5
The period of this function will be (2pi)/5, because for every (2pi)/5 change in the value of x, the function will have the same value. The value of 5 multiplying the cosine does not interfere in the period.
You should have a calculator on your phone or pc.
2098800
The two inequalities can be rewritten as

The solution is composed by every point below the graph of the line
, and above the horizontal line 
To draw the line
we can build a little table (only 2 points are required):

So, if you draw the points (0,2) and (1, -2) and connect them, you'll have your line.
To draw the line
, simply pick any point with y coordinate -2, for example (0, -2), and draw a horizontal line.
Choose the above/below areas as specified above to solve the system.
Answer:
I am pretty sure its 30 students