Exponential Functions

Which graph shows an exponential function?

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What is the y-intercept of the following exponential function?

 $y=3^x$  

•  $y=3$  

•  $y=1$  

•  $x=3$  

•  $x=1$  

Which graph represents the exponential function

 $y=\left(\frac{1}{4}\right)^x$  

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What does the following exponential function represent?

 $y=1200\left(1.05\right)^x$  

• Exponential Growth

• Exponential Decay

• Cannot be determined

What can be concluded from the following exponential expression? (Select all that apply)

 $y=1200\left(1.05\right)^x$  

• The initial amount is 1200

• The initial amount is 1.05

• The rate of growth is 5%

• The rate of growth is 1.05%

What does the following exponential function represent?

 $y=2400\left(0.85\right)^x$  

• Exponential Growth

• Exponential Decay

• Cannot be determined

What can be concluded from the following exponential expression? (Select all that apply)

 $y=2400\left(0.85\right)^x$  

• The initial amount is 0.85

• The initial amount is 2400

• The rate of decay is 15%

• The rate of decay is 85%

The population of New York City has increased by a rate of about 0.4% per year after the year 2000. If the population of New York City was 8,008,268 people in the year 2000, which equation represents the population t years after 2000?

• $8,009,278\left(1.4\right)^t$

• $8,008,278\left(1.004\right)^t$

• $\left(1.004\right)^t$

• $8,008,278\left(0.4\right)^t$

The population of New York City has increased by a rate of about 0.4% per year after the year 2000. If the population of New York City was 8,008,268 people in the year 2000, use the equation from the previous question to predict the population of New York City in 2015.

• about 8,502,465

• about 11,212,220

• about 8,300,235

• about 3,203,491

Determine the amount of an investment if $300 is invested at an interest rate of 6.75% compounded semiannually for 20 years. (use the compound interest formula) $A=P\left(1+\frac{r}{n}\right)^{nt}$  

• about $628

• about $1,108

• about $1,132

• about $4,091