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Concept explainers
In Exercises 6—10, we consider the phenomenon of radioactive decay which, from experimentation, we know behaves according to the law:
The rate at which a quantity of a radioactive isotope decays is proportional to the amount of the isotope present. The proportionality constant depends only on which radioactive isotope is used.
7. The half-life of a radioactive isotope is the amount of time it takes for a quantity of radioactive material to decay to one-half of its original amount.
(a) The half-life of Carbon 14 (C-14) is 5230 years. Determine the decay-rate pa-rameter
(b) The half-life of Iodine 131 (I-131) is 8 days. Determine the decay-rate param-eter for I-131.
(c) What are the units of the decay-rate parameters in parts (a) and (b)?
(d) To determine the half-life of an isotope, we could start with atoms of the isotope and measure the amount of time it takes 500 of them to decay, or we could start with 10,000 atoms of the isotope and measure the amount of time it takes 5000 of them to decay. Will we get the same answer? Why?
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Chapter 1 Solutions
Differential Equations
- A marketing professor has surveyed the students at her university to better understand attitudes towards PPT usage for higher education. To be able to make inferences to the entire student body, the sample drawn needs to represent the university’s student population on all key characteristics. The table below shows the five key student demographic variables. The professor found the breakdown of the overall student body in the university’s fact book posted online. A non-parametric chi-square test was used to test the sample demographics against the population percentages shown in the table above. Review the output for the five chi-square tests on the following pages and answer the five questions: Based on the chi-square test, which sample variables adequately represent the university’s student population and which ones do not? Support your answer by providing the p-value of the chi-square test and explaining what it means. Using the results from Question 1, make recommendation for…arrow_forwardQuestion 10 6 5 4 3 2 -π/4 π/4 π/2 -1 -2 -3- -4 -5- -6+ For the graph above, find the function of the form f(x)=a tan(bx)+c where a=-1 or +1 only f(x) = Question Help: Videoarrow_forwardMODELING REAL LIFE Your checking account has a constant balance of $500. Let the function $m$ represent the balance of your savings account after $t$ years. The table shows the total balance of the accounts over time. Year, $t$ Total balance 0 1 2 3 4 5 $2500 $2540 $2580.80 $2622.42 $2664.86 $2708.16 a. Write a function $B$ that represents the total balance after $t$ years. Round values to the nearest hundredth, if necessary. $B\left(t\right)=$ Question 2 b. Find $B\left(8\right)$ . About $ a Question 3 Interpret $B\left(8\right)$ . b represents the total balance checking and saving accounts after 8 years the balance would be 16 / 10000 Word Limit16 words written of 10000 allowed Question 4 c. Compare the savings account to the account, You deposit $9000 in a savings account that earns 3.6% annual interest compounded monthly. A = 11998.70 SINCE 9000 is the principal ( 1+0.036/12)12 times 8 gives me aproxtimately 1997 14 / 10000 Word Limit14 words written of 10000 allowed Skip to…arrow_forward
- Listen MODELING REAL LIFE Your checking account has a constant balance of $500. Let the function m represent the balance of your savings account after t years. The table shows the total balance of the accounts over time. Year, t Total balance 0 $2500 1 $2540 2 $2580.80 3 $2622.42 4 $2664.86 5 $2708.16 a. Write a function B that represents the total balance after t years. Round values to the nearest hundredth, if necessary. B(t) = 500 + 2000(1.02)* b. Find B(8). About $2843.32 Interpret B(8). B I U E T² T₂ c. Compare the savings account to the account, You deposit $9000 in a savings account that earns 3.6% annual interest compounded monthly. B I U E E T² T₂ A = 11998.70 SINCE 9000 is the principal (1+0.036/12)12 times 8 gives me aproxtimately 1997arrow_forward14. Show that if a, b, and c are integers such that (a, b) = 1 and c | (a+b), then (c, a) = (c, b) = 1.arrow_forwardA retail chain is interested in determining whether a digital video point-of-purchase (POP) display would stimulate higher sales for a brand advertised compared to the standard cardboard point-of-purchase display. To test this, a one-shot static group design experiment was conducted over a four-week period in 100 different stores. Fifty stores were randomly assigned to the control treatment (standard display) and the other 50 stores were randomly assigned to the experimental treatment (digital display). Compare the sales of the control group (standard POP) to the experimental group (digital POP). What were the average sales for the standard POP display (control group)? What were the sales for the digital display (experimental group)? What is the (mean) difference in sales between the experimental group and control group? List the null hypothesis being tested. Do you reject or retain the null hypothesis based on the results of the independent t-test? Was the difference between the…arrow_forward
- Using fixed point iteration and Newton Raphson methods to solve the following function: f(x) = e−0.5x(4-x)-2. Take xo-2 and n=5.arrow_forwardUse the information to find and compare Δy and dy. (Round your answers to four decimal places.) y = x4 + 7 x = −3 Δx = dx = 0.01 Δy = dy =arrow_forwardWhat were the average sales for the four weeks prior to the experiment? What were the sales during the four weeks when the stores used the digital display? What is the mean difference in sales between the experimental and regular POP time periods? State the null hypothesis being tested by the paired sample t-test. Do you reject or retain the null hypothesis? At a 95% significance level, was the difference significant? Explain why or why not using the results from the paired sample t-test. Should the manager of the retail chain install new digital displays in each store? Justify your answer.arrow_forward
- Solve the following Probability Problem (solve all parts) HW 2.x. (Headless Hunt)The Headless Hunt is an organization of 88 Hogwarts ghosts so elite thateven Nearly Headless Nick was annually denied admission for decades,despite being The Gryffindor ghost. The ghosts love playing sports anddecided to get together and have either a Head Polo tournament or aHorseback Head-Juggling tournament. However, even if they are ghosts,they still have jobs so some of them might have an urgent haunting as-signment. In order for no one to be left behind they need to be able tosplit into teams of equal numbers. Head polo teams consist of 4 playerswhereas Horseback Head-Juggling teams have 11 players. Assume thatany number of them from 1 to 88 show up with equal probability. a) What is the probability they will be able to play one of the twotournaments?b) If in addition to the previous 2 sports there was one more option, atournament in Headless bowling which is played in teams of 8 players,what would…arrow_forwardCan you evalutate the following summation:∑_{y=1}^{x} 2 / ((x + y - 1)(x + y + 1))arrow_forwardA retail chain is interested in determining whether a digital video point-of-purchase (POP) display would stimulate higher sales for a brand advertised compared to the standard cardboard point-of-purchase display. To test this, a one-shot static group design experiment was conducted over a four-week period in 100 different stores. Fifty stores were randomly assigned to the control treatment (standard display) and the other 50 stores were randomly assigned to the experimental treatment (digital display). Compare the sales of the control group (standard POP) to the experimental group (digital POP). What were the average sales for the standard POP display (control group)? What were the sales for the digital display (experimental group)? What is the (mean) difference in sales between the experimental group and control group? List the null hypothesis being tested. Do you reject or retain the null hypothesis based on the results of the independent t-test? Was the difference between the…arrow_forward
- Algebra and Trigonometry (MindTap Course List)AlgebraISBN:9781305071742Author:James Stewart, Lothar Redlin, Saleem WatsonPublisher:Cengage LearningAlgebra & Trigonometry with Analytic GeometryAlgebraISBN:9781133382119Author:SwokowskiPublisher:Cengage
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