Question

An ice cream truck that plays loud music is circling Bulans neighborhood. C(t) models the volume of the music in dB that Bulan hears, t minutes after the truck arrives in her neighborhood. Here T is entered in radians C(t)=-15cos(2pi/15t)+65 how many minutes after te truck arrives does the volume reach 75

Answer 1

5.5 minutes

Explanation:

Fill in the given information and solve for t.

75 = -15cos(2πt/15) +65

-10/15 = cos(2πt/15)

t = 15/(2π)arccos(-2/3) ≈ 5.492

The volume reaches 75 dB about 5.5 minutes after the truck arrives.