Summary of Derivatives of Exponential and Logarithmic Functions

Essential Concepts

  • On the basis of the assumption that the exponential function y=bx,b>0 is continuous everywhere and differentiable at 0, this function is differentiable everywhere and there is a formula for its derivative.
  • We can use a formula to find the derivative of y=lnx, and the relationship logbx=lnxlnb allows us to extend our differentiation formulas to include logarithms with arbitrary bases.
  • Logarithmic differentiation allows us to differentiate functions of the form y=g(x)f(x) or very complex functions by taking the natural logarithm of both sides and exploiting the properties of logarithms before differentiating.

Key Equations

  • Inverse function theorem
    (f1)(x)=1f(f1(x)) whenever f(f1(x))0 and f(x) is differentiable.
  • Power rule with rational exponents
    ddx(xm/n)=mnx(m/n)1.
  • Derivative of the natural exponential function
    ddx(eg(x))=eg(x)g(x)
  • Derivative of the natural logarithmic function
    ddx(ln(g(x)))=1g(x)g(x)
  • Derivative of the general exponential function
    ddx(bg(x))=bg(x)g(x)lnb
  • Derivative of the general logarithmic function
    ddx(logb(g(x)))=g(x)g(x)lnb

Glossary

logarithmic differentiation
is a technique that allows us to differentiate a function by first taking the natural logarithm of both sides of an equation, applying properties of logarithms to simplify the equation, and differentiating implicitly