# Example: Growth or Decay

*T*(

*q*) represents the total number of Android smart phone contracts, in thousands, held by a certain Verizon store region measured quarterly since January 1, 2010. Interpret all of the parts of the equation

*T*(2) = 86(1.64)

^{2}= 231.3056. Interpreting this from the basic exponential form, we know that 86 is our initial value. This means that on Jan. 1, 2010, this region had 86,000 Android smart phone contracts. Since

*b*= 1 +

*r*= 1.64, we know that every quarter the number of smart phone contracts grows by 64%.

*T*(2) = 231.3056 means that in the second quarter (or at the end of the second quarter) there were approximately 231,305 Android smart phone contracts. Shana Calaway, Dale Hoffman, and David Lippman, Business Calculus, " 1.7: Exponential Functions," licensed under a CC-BY license.