Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
The natural logarithm function, denoted as ln x, is the inverse of the exponential function with base e. It gives the value of y such that e raised to the power of y equals x.
Related terms
Exponential function: A mathematical function where a constant base is raised to a variable exponent. For example, f(x) = 2^x is an exponential function.
Logarithmic function: A mathematical function that represents the inverse relationship between exponentiation and logarithms. It allows us to solve for exponents when given a base and result.
Base e (Euler's number): A special irrational number approximately equal to 2.71828... It is commonly used in calculus and plays a significant role in exponential growth and decay functions.