Chapter 8: Problem 43
Find the sum for each series. $$\sum_{i=1}^{5}\left(3^{i}-4\right)$$
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Chapter 8: Problem 43
Find the sum for each series. $$\sum_{i=1}^{5}\left(3^{i}-4\right)$$
These are the key concepts you need to understand to accurately answer the question.
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What will happen when an infectious disease is introduced into a family? Suppose a family has \(I\) infected members and \(S\) members who are not infected, but are susceptible to contracting the disease. The probability \(P\) of \(k\) people not contracting the disease during a 1-week period can be calculated by the formula. $$P=\left(\begin{array}{l}S \\\k\end{array}\right) q^{k}(1-q)^{S-k}$$ where \(q=(1-p)^{l}\) and \(p\) is the probability that a susceptible person contracts the disease from an infectious person. For example, if \(p=0.5,\) then there is a \(50 \%\) chance that a susceptible person exposed to one infectious person for 1 week will contract the disease. (Source: Hoppensteadt, F. and C. Peskin, Mathematics in Medicine and the Life Sciences, Springer-Verlag.) (a) Approximate the probability \(P\) of 3 family members not becoming infected within 1 week if there are currently 2 infected and 4 susceptible members. Assume that \(p=0.1\) (b) A highly infectious disease can have \(p=0.5 .\) Repeat part (a) with this value of \(p\) (c) Approximate the probability that everyone would become sick in a large family if initially \(I=1, S=9\) and \(p=0.5\)
Solve each problem . (Modeling) Investment for Retirement According to T. Rowe Price Associates, a person who has a moderate investment strategy and \(n\) years until retirement should have accumulated savings of \(a_{n}\) percent of his or her annual salary. The geometric sequence $$ a_{n}=1276(0.916)^{n} $$ gives the appropriate percent for each year \(n\) (a) Find \(a_{1}\) and \(r\) (b) Find and interpret the terms \(a_{10}\) and \(a_{20}\)
Prove each statement for positive integers \(n\) and \(r,\) with \(r \leq n\) (Hint: Use the definitions of permutations and combinations.) $$C(n, n-1)=n$$
Prove each statement for positive integers \(n\) and \(r,\) with \(r \leq n\) (Hint: Use the definitions of permutations and combinations.) $$C(n, n)=1$$
Find \(a_{1}\) for each arithmetic sequence. $$a_{6}=-8, a_{7}=-18$$
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