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Explore exponential functions with practical examples like investment growth, money doubling, and car depreciation. Learn the equations, formulas, and calculations to predict value changes over time. Enhance your math skills for real-world applications.
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Do Now • Three years ago you bought a Lebron James card for $45. It has appreciated (gone up in value) by 20% each year since then. How much is worth today?
Exponential Growth & Decay Applications that Apply to Me!
Exponential Functions • Always involves the equation: bx • Example: • 23 = 2 · 2 · 2 = 8
Group investigation:Y = 2x • Create an x,y table. • Use x values of -1, 0, 1, 2, 3, • Graph the table • What do you observe.
Observations • What did you notice? • What is the pattern? • What would happen if x= -2 • What would happen if x = 5 • What real-life applications are there?
Group: Money Doubling? • You have a $100.00 • Your money doubles each year. • How much do you have in 3 years? • Show work.
Money Doubling Year 1: $100 · 2 = $200 Year 2: $200 · 2 = $400 Year 3: $400 · 2 = $800
Earning Interest on • You have $100.00. • Each year you earn 10% interest. • How much $ do you have in 3 years? • Show Work.
Earning 10% results Year 1: $100 + 100·(.10) = $110 Year 2: $110 + 110·(.10) = $121 Year 3: $121 + 121·(.10) = $133.10
Exponential Growth Model The Formula is: y = a(1+r)t a = Initial Amount r = Growth Rate (1+r) = Growth Factor t = Time Period
Using the Equation • $100.00 • 10% interest • 5 years • 100(1+ (.10))5 = $161.05 • What could we figure out now?
Exponential Decay Model Instead of increasing, it is decreasing. Formula: y = a(1–r)t a = Initial Amount r = Decay Rate (1-r) = Decay Factor t = Time Period
Real-life Examples • What is car depreciation? • Car Value = $20,000 • Depreciates 10% a year • Figure out the following values: • After 2 years • After 5 years • After 8 years • After 10 years
Exponential Decay: Car Depreciation Assume the car was purchased for $20,000 Formula: y = a (1 – r)t a = initial amount r = percent decrease t = number of years
Homework Textbook: • Page 481 #24-28 • Page 489 #26-30