Question 997592
Variable stars are ones whose brightness varies periodically. The brightness of a certain star is modeled by the function
b(t) = 8.1 − 2.2 cos (pi/155)t
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Not clear.
Clarify the cosine.
pi/155 is a constant.


where t is measured in days.
(a) Find the period.
 
 days

(b) Find the maximum and minimum brightness.
 
 (minimum)
 
 (maximum)

(c) Graph the function b.