
Steve S. answered 03/27/14
Tutor
5
(3)
Tutoring in Precalculus, Trig, and Differential Calculus
“Given the geometric sequence:
14, (140/11), (1400/121),…
Find an explicit formula for An
Find A11”
r = (140/11)/14 = (1400/121)/(140/11) = 10/11
An = 14(10/11)^(n-1), n a positive integer
[Note: 0 is neither positive nor negative.]
A11 = 14(10/11)^(11-1)
A11 = 14(10/11)^10 = 14*10^10/11^10
A11 = (140,000,000,000)/(25,937,424,601)
A11 ≈ 5.39760605201344
14, (140/11), (1400/121),…
Find an explicit formula for An
Find A11”
r = (140/11)/14 = (1400/121)/(140/11) = 10/11
An = 14(10/11)^(n-1), n a positive integer
[Note: 0 is neither positive nor negative.]
A11 = 14(10/11)^(11-1)
A11 = 14(10/11)^10 = 14*10^10/11^10
A11 = (140,000,000,000)/(25,937,424,601)
A11 ≈ 5.39760605201344