Precalculus A Fuctional Approach to Graphing and Problem Solving

Section 4.7: Exponential Real Numbers
Essential Ideas
  • Exponential Equations
    Exp Type I:   Base 10, use common logarithm.
    Exp Type II: Base e, use natural logarithm.
    Exp Type III: Base b, use change of base theorem.

  • Growth/Decay Formula
    Exponential growth or decay can be described by the equation
                                         A = A0ert
    where r is the annual growth/decay rate, t is the time (in years), A0 is the amount present initially (present value), and A is the future value. If r is positive, this formula models growth, and if r is negative, the formula models decay.

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© 2011 Karl J. Smith. All rights reserved.