Exponential Functions Card Sort Note: Print copies of Page 2 as a recording sheet. Each group should fill in the information for each lettered situation. Print pages 3 – 58 after setting the printer for Portrait, 6 Slides to a Page to create group cards. The powerpoint has the cards in the correct order (key). Cut each set apart and shuffle. Note that there are 2 extra equation cards that are not correct for any of the situations. The 9 sets of cards should be matched to show: A real-world situation A label of “growth” or “decay” The equation for the situation The graph of the situation The table of values for the graph The solution to the situation

Exponential Growth or Decay? y-intercept and asymptote Situation Exponential Growth or Decay? Equation y-intercept and asymptote 3 pairs from the table Solution A B C D E F G H I

Situation A Find a bank account balance if the account starts with $100, has an annual rate of 4%, and the money is left in the account for 12 years.

Exponential Growth

y=100(1.04)x

160.10

Situation B In 1985, there were 285 cell phone subscribers in the small town of Centerville. The number of subscribers increased by 75% per year after 1985. How many cell phone subscribers were in Centerville in 1994?

Exponential Growth

y=285(1.75)x

43872

Situation C Bacteria can multiply at an alarming rate when each bacteria splits into two new cells, thus doubling. If we start with only one bacteria which can double every hour, how many bacteria will we have by the end of one day?

Exponential Growth

y=1(2)x

16777216

Situation D Each year the local country club sponsors a tennis tournament. Play starts with 128 participants. During each round, half of the players are eliminated. How many players remain after 5 rounds?

Exponential Decay

y=128(1/2)x

4

Situation E You have inherited land that was purchased for $30,000 in 1960. The value of the land increased by approximately 5% per year. What is the approximate value of the land in the year 2011?

Exponential Growth

y=30000(1.05)x

361223.09

Situation F You drink a beverage with 120 mg of caffeine. Each hour, the caffeine in your system decreases by about 12%. How long until you have 10 mg of caffeine left in your system?

Exponential Decay

y=120(0.88)x

19.44

Situation G An adult takes 400 mg of ibuprofen. Each hour, the amount of ibuprofen in the person’s system decreases by about 29%. About how many grams of ibuprofen are left in the system after 6 hours?

Exponential Decay

y=400(0.71)x

51.24

Situation H You buy a new computer for $2100. The value of the computer decreases by 50% annually. In how many years will the computer have a value of $600?

Exponential Decay

y=2100(0.50)x

1.81

Situation I You deposit $1500 in an account that pays 5% interest yearly. How much money do you have in the account after 6 years?

Exponential Growth

y=1500(1.05)x

2010.10

y=120(1.12)x

y=30000(.05)x