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a sound wave is modeled with the equation y = 1/4 cos 2 pi/3 theta

a. find the period. explain your method.
b. find the amplitude. explain your method.
c. what is the equation of the midline? what does it represent?

i really need on this one!

Hi my sisters and brothers can tell me the answer because i don’t understand the question

14 pointslet x be the seats in the small van and y the seats in the large van. how many seats does the large van have? a company uses two vans to transport worker from a free parking lot to the workplace between 7: 00 and 9: 00a.m. one van has 9 more seats than the other. the smaller van makes two trips every morning while the larger one makes only one trip. the two vans can transport 69 people, maximum.how many seats does the larger van have?

Proceed as in example 3 in section 6.1 to rewrite the given expression using a single power series whose general term involves xk. ∞ n(n − 1)cnxn − 2 n = 2 − 4 ∞ ncnxn n = 1 + ∞ cnxn n = 0