FST 2-4B

FST 2-4B Day 2 Notes

Exponential Function

Exponential Function

• y = ab^x

• a = initial value or initial amount

• b = 1 + r, b > 1, if it is exponential growth, y = 2(4)^x

• b= 1 - r, 0<b<1, if it is exponential decay, y = 2(0.5)^x

• r is just rate in decimal, such as 10% increase, or 35% decrease

• How do you find a from the graph? It is just y-intercept.

Multiple Select

Which of the followings are exponential functions?

• k(j) = 3^j

• h(x) = 5x²

• p(t) = 2(1/3)^x

• y = 3x - 10

How do you graph y=3^x

• Create a table from x = -2,-1,0,1,2

• Plot points (-2, 1/9) (-1, 1/3) (0, 1) (1, 3) (2, 9)

• Label Horizontal Asymptote HA) y = 0

Multiple Select

Identify whether the following are growth.

• y=3(1/2)^x

• y=(1/2)(3)^x

• y = 2(6.3)^x

• y=500(0.02)^x

Multiple Select

Identify whether the following are decay.

• y=3(1/2)^x

• y=(1/2)(3)^x

• y = 2(6.3)^x

• y=500(0.02)^x-2

Fill in the Blank

In 1950, Brea's population was 3,208 and it grew at a rate of 4.9% per year. Write an exponential functio to represent growth in t years. Remember that y = ab^x

Fill in the Blank

In 1950, Brea's population was 3,208 and it grew at a rate of 4.9% per year. Using previous exponential equation, predict the population in 2010. Remember to use x as # of years since 1950.

Multiple Select

Find an exponential using a graphing calculator. Don't forget to do Stat Edit L1, L2, then Stat Calc ExpReg for an exponential function or model.

• P= 10(10)^h

• P = 2(10)^h

• P = 10(2)^h

• P = 2(2)^h