Quick Check: Day 15 Exponential Functions

Mathematical Equivalence

ON

• Growth

• Decay

Which of the following functions shows an initial amount of $15 and an increase of 35% each year?

• y = 15(35)^x
• y = 15(1.35)^x
• y = 15(0.35)^x
• y = 35(1.15)^x

Classify the model as Exponential GROWTH or DECAY.
A=1200(.85)⁶

• Growth
• Decay

Write an equation that models the following situation:
Samantha's hair was known to grow very rapidly. It began at a length of 6 in and grew at a rate of 14% a week.

• y=6(0.14)^x
• y=6(1+14)^x
• y=6(1.14)^x
• y=6(0.86)^x

Identify the initial value:

y = 6.87 (4)^x

• a = 4

• a = 6.87

• a = 3

• a = 1

The function y = 125(1.13)^x represents Mr. Gantz's recent investments where x is measured in years.  Which is NOT true?

• Mr. Gantz initial invested $125
• Mr. Gantz's money grows by 13% per year
• After 4 years Mr. Gantz will have about $203.81
• Mr. Gantz earns more money in year one than in year 5

Identify the y-intercept (initial value) in the function f(x)=13(.27)^x

• (.27)^x
• .27
• 13
• 3.51

Write an equations that models the data shown.

Suppose the population of a species of insects doubles every year. There are 1600 insects initially. The function for the scenario would be?