Presentation on theme: "Suggested Activities Unit 2: Algebra Essentials. Rate of Change An Introduction to Slope."— Presentation transcript:
Suggested Activities Unit 2: Algebra Essentials
Rate of Change An Introduction to Slope
Schema Activator A rate of change is a ratio that shows a change in one quantity with respect to a change in another quantity. Examples: hours worked vs. dollars earned miles ran vs. calories burned miles traveled vs. fuel in tank weight in pounds vs. price of bananas List 2 examples of your own.
Rate of Change Independent variables are quantities that are manipulated or changed. hours worked miles ran miles traveled weight in pounds Dependent variables are quantities that are changed as a result of manipulating the independent variable. dollars earned calories burned fuel in tank price of bananas
Rate of Change: WRITE THIS DOWN! Rate of Change = Change in Dependent Variable Change in Independent Variable RATIO!
Independent variable? Dependent? The rate of change is constant in the table. Find the rate of change. What does this tell us? Rate of Change: Example 1 Time (hours) Temperature (F)
Independent variable? Dependent? The rate of change is constant in the table. Find the rate of change. What does this tell us? Rate of Change: Example 2 PeopleCost (dollars)
Rate of Change: You Try It! Number of DaysRental Charge 1$60 2$75 3$90 4$105 5$120 The rate of change is constant in each table. Find the rate of change. Miles RanCalories Burned
Facebook Challenge: The Solution
The graph below represents the value of an iPad based on the number of years that have passed since it was originally purchased. 1. Calculate the rate of change as shown in the graph. 2. What is the y-intercept? 3. What does it mean in the context of this problem?
Materials your team needs: 1. A Slinky 2. A foam cup 3. Pennies Your task: 1. Attach the foam cup to one end of the Slinky. 2. Hang the Slinky from a doorway, ceiling, corner of the room, etc. 3. Measure the length of the Slinky from one end to the other (where the Slinky meets the cup). 4. Add one penny to the cup. 5. Measure the length of the Slinky again – record! 6. Repeat steps 4-5 to fill in the data table. Tonights homework: 1. Graph your data. Include labeled axes and a title! 2. Remember: (# of pennies is the independent variable, so it should be on the x-axis!)
Return to your Slinky team. Compare each others graphs. Do they look the same? If not, what could be a cause for the variation between graphs? Do you see any pattern(s) when comparing the number of pennies to the length of the Slinky? Can you identify the independent/dependent variables? Select one graph to represent your teams findings. Be prepared to share.
How much do you owe?
Fill in your traffic ticket. In the SPEED LIMIT box list 65. Make up your own ALLEGED SPEED … how fast were you actually driving? What type of car were you driving? Be creative!
The fine for speeding in your state is $85 plus $5 for each mile above the speed limit you were driving. Calculate how much you need to pay. Lets compare our answers.
Can we write an equation that can be used to calculate any amount due based on the drivers speed? Whats the equation? Hint: Notice that you must pay $85 regardless of your speed, in addition to $5 for every mile over the speed limit. Use a variable to represent the speed at which youre traveling.
Amount Owed = 85 + (Your Speed – 65) 5 Or, we can write it like this: y = (s – 65) Now, lets graph that equation. Set your window to: Xmin= 0 Xmax= 120 Xscl= 20 Ymin= 0 Ymax= 200 Yscl= 20 Xres= 1
Using the Table feature on your calculator, about how much would somebody owe if they were driving: 101 mph? 90 mph? 85 mph? Check your predictions by substituting for the variable s in our equation: y = (s – 65)
Schema Activator Do the following exponential functions represent growth or decay? (Think about the car and bank account examples weve worked on.) 1. y = (1.08) x 2. y = (½) x 3. y = (0.25) x 4. y = ½(8) x 5. y = (¼) x
Team 1 Population: The population of the popular town of Jersey City in 2008 was estimated to be 250,000 people with an annual rate of increase (growth) of about 2.4%. 1.Write an equation that models the population P based on the number of years x following How many people would you expect to be living in Jersey City in 2012? 3.High-Five Challenge: How long will it take for Jersey Citys population to double?
Team 2 Money: Jeiny invests $300 at a bank that offers 5% interest compounded annually. 1.Write an equation to model the growth of the investment. 2.What would be the value of Angelis account after 8 years? 3.High-Five Challenge: After how many years will Angelis account be worth four times her initial investment?
Team 3 Cars: Matt bought a new car at a cost of $25,000. The car depreciates approximately 15% of its value each year. 1.Write an equation that models the decay of the cars value. 2.What will be the value of the car in 4.5 years? 3.How much money did Matt lose? 4.High-Five Challenge: When will the value of Matts car first fall below $3,500?
Team 4 More Money: Jordi invests $1,285 at a bank that offers 4.25% interest compounded annually. 1.Write an equation to model the growth of the investment. 2.What would be the value of Wills account after 2 years? 3.High-Five Challenge: What is the minimum interest rate at which Will should invest $1,285 to have at least $1,500 after 3 years?
Exploring Quadratics 1. Today you will explore the graph of a quadratic function. 2. In groups of 6, you will complete the Kitchen Paraboloids handout and answer the questions that follow. 3. Group member roles: 1. Water pourer 2. Measurement master 3. Data recorder 4. Results reporter