14 81.92 10. The frequencies produced by the musical pitch A in ascending octaves make up a 15 163. 84 geometric sequence. A. The lowest A pitch that can be heard by the human ear is AO. What is Scale of A's the frequency of AO? Pitch Frequency (Hz) AO ? B. Write a geometric sequence for the frequency of A pitches in hertz A1 55 where n = 1 represents Al. A2 110 A3 220 C. Humans cannot hear sounds with frequencies greater than 20,000 Hz. A4 440 What is the first A pitch that humans cannot hear? 11. The average cost of a pound of chicken at a new grocery store was $4 its first year in business. Assume the cost per pound of chicken is expected to increase by 2% per year. A. What information do you use to model the expected cost of a pound of chicken in the store's nth year of business? B. What is the general rule for the geometric sequence? C. Is it reasonable in this context to calculate a(50) as the expected cost when n = 50? Why or why not? D. What are the domain and range of the geometric sequence? Houghton Mifflin HInteractive For Problems 1-4, use the given information about each geometric sequence to find the value of the specified term. Round to the nearest thousandth if necessary. Show your work. 1. a(1) = 625 71= 163:4 2. a,= -12 r = 0.8 r = 2.5 Find a (7). Find a 10. 3. a = 144 4. a (3) = 15 r = 3 a(5) = 540 Find ag. Find a(11). Each graph below shows terms of an infinite geometric sequence. Find the specified term of each sequence. 1 (8 )h-l 5. What is the 9th term? 6. What is the 11th term? 2 2 48 20 8 - (1, 8) 832 . (2, 7.2) 10 (3 9) 6 . (3, 6.48) (4, 5.832) . (1, 4) X 4 0 4 6 10 (2 -6) X 20 (4, -13.5) 6 8 For Problems 7 and 8, use the given information about each geometric sequence to find the sum of the first n terms specified. Round to the nearest thousandth if necessary. 7. a(n) = 10 ; Find S10. 8. an = 9"-; Find Sg