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.
