Concept explainers
Reminder Round all the answers to two decimal places unless otherwise indicated.
Sales Growth A class of models for population growth rates in marine fisheries assumes that the harvest from fishing is proportional to the population size One such model uses a quadratic function:
Here
a. Make a graph of
b. Calculate
c. At what population size is the growth rate the largest?
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Functions and Change: A Modeling Approach to College Algebra (MindTap Course List)
- Alligators Refer to Exercise 93. If an alligator weighs 125 pounds, what is its approximate length? Round to the nearest inch. 93. Alligators The length in inches and weight in pounds of 25 alligators is shown in the table. Find the quadratic function that best fits the data. Round a,b, and c to six decimal places. Use the regression function to estimate the weight of an alligator that is 130 inches long. Round the weight to the nearest pound. Length Weight Length Weight Length Weight 94 130 72 38 90 106 74 51 128 366 89 84 147 640 85 84 68 39 58 28 82 80 76 42 86 80 86 83 114 197 94 110 88 70 90 102 63 33 72 61 78 57 86 90 74 54 69 36 61 44arrow_forwardFlood Control A river is 8 feet above its flood stage. The water is receding at a rate of 3 inches per hour. Write a mathematical model that shows the number of feet above flood stage after t hours. Assuming the water continually recedes at this rate, when will the river be 1 foot above its flood stage?arrow_forwardLIFE SCIENCE APPLICATIONS Gender Ratio The number of males per 100 females, age 65 or over, in the United States for some recent years is shown in the following table. Source: The U.S Census Bureau. Year Males per 100 Females 1960 82.8 1970 72.1 1980 67.6 1990 67.2 2000 70.0 2010 77.0 a. Plot the data, letting x be the years since 1900. b. Would a linear or quadratic function best model this data? Explain. c. If your graphing calculator has a quadratic regression feature, find the quadratic function that best fits the data. Graph this function on the same calculator window as the data. See Example 7c. d. Choose the lowest point in the table above as the vertex and 110,77.0 as a second point to find a quadratic function defined by f(x)=a(xh)2+k that models the data. e. Graph the function from part d on the same calculator window as the data and function from part c. Do the graphs of the two functions differ by much? f. Predict the number of males per 100 females in 2004 using the two functions from parts c and d, and compare with the actual figure of 71.7.arrow_forward
- TEST YOUR UNDERSTADING FOR EXAMPLE 3.5 A donation to the university is required for the privilege of purchasing premium season football passes. The cost is a linear function of the number of season passes. It costs 8000 to get season passes for myself and my spouse. To get passes for my entire family of 5, it costs 17,000. Use a formula to express the total cost C, in dollars, of n season passes. EXAMPLE 3.5 CHANGING CELSIUS TO FAHRENHEIT Temperature F=F(C) in Fahrenheit is a linear function of the temperature C in Celsius. A lab assistant placed a Fahrenheit thermometer beside a Celsius thermometer and observed the following: When the Celsius thermometer reads 30 degree (C=30), the Fahrenheit thermometer reads 86 degrees (F=86). When the Celsius thermometer reads 40 degrees, the Fahrenheit thermometer reads 104 degrees. Part 1 Use a formula to express F as a linear function of C. Part 2 At sea level, water boils at 212 degrees Fahrenheit. What temperature in degrees Celsius makes water boil? Part 3 Explain in practical terms what the slope means in this setting.arrow_forwardHealth Plan The manager of an employee health plan for a firm has studied the balance B, in millions of dollars, in the plan account as a function of t, the number of years since the plan was instituted. He has determined that the account balance is given by the formula B=60+7t50e0.1t a. Make a graph of B versus t over the first 7 years of the plan. b. At what time is the account balance at its maximum? c. What is the smallest value of the account balance over the first 7 years of the plan?arrow_forwardEarthquake the graph shows the vertical acceleration of the Ground from the 1994 Northridge earthquake in Los Angles, as measured by a seismograph. (Here t represents the time in seconds.) (a) At what time t did the earthquake first make noticeable movement of the Earth? (b) At what time t did the earthquakes seem to end? (c) At what time t was the maximum intensity of the earthquake list reachedarrow_forward
- Immigration The following graph shows immigrationin thousand to the United States has varied over the past century. Source: Homeland Security. a. Find the average annual rate of change in immigration for the first half of the century from 1905 to 1955. b. Find the average annual rate of change in immigration for the second half of the century from 1955 to 2005. c. Find the average annual rate of change in immigration for the entire century from 1905 to 2005. d. Average your answers to part a and b, and compare the result with your answer from part c. Will these always be equal for any two time periods? e. If the annual average rate of change for entire century continues, predict the number of immigrants in 2009. Compare answer to the actual number of 1,130,818 immigrants.arrow_forwardLIFE SCIENCE APPLICATIONS Milk Consumption The average individual daily milk consumption for herds of Charolaise, Angus, and Hereford calves can be by the function. M(t)=6.281t0.242e0.025t, 1t26 Where M(t) is the milk consumption in kilograms and t is the age of the calf in weeks. Source: Animal Production. a. Find the time in which the maximum daily consumption occurs and the maximum daily consumption. b. If the general formula for this model is given by M(t)=atbect Find the time where the maximum consumption occurs and the maximum consumption.Hint: Express your answer in terms of a ,b and c.arrow_forward
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- College Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage LearningTrigonometry (MindTap Course List)TrigonometryISBN:9781337278461Author:Ron LarsonPublisher:Cengage Learning