We have changed our privacy policy. In addition, we use cookies on our website for various purposes. By continuing on our website, you consent to our use of cookies. You can learn about our practices by reading our privacy policy.
© 2016 Shmoop University, Inc. All rights reserved.

Common Core Standards: Math See All Teacher Resources

High School: Functions

Interpreting Functions F-IF.8b

b. Use the properties of exponents to interpret expressions for exponential functions. For example, identify percent rate of change in functions such as y = (1.02)t, y = (0.97)t, y = (1.01)12t, y = (1.2)t10 and classify them as representing exponential growth or decay.

If we have a function of the form y = abx, we can either be describing exponential growth or exponential decay. If a > 0 and 0 < b < 1, the equation represents decay. If a > 0 and b > 1, the equation represents growth.

Equations like y = a(1 + c)x can represent the balance of a savings account after x years with starting balance a and interest rate c. If the annual interest rate is 2% and we start with $100, how much money will we have in 10 years? Just substitute in our values, and we're good to go.

y = a(1 + c)x = 100(1 + 0.02)10 = $121.90

Not too bad, but don't go spending it all on bubble gum. We may want to save up for a new iPod. Or to pay for Coach Gibson's medical bills.

Aligned Resources

    More standards from High School: Functions - Interpreting Functions