Math

Natural log.

Definition

The natural logarithm (ln) is the logarithm with base e, where e ≈ 2.71828. It answers the question: to what power must e be raised to get a given number?

Examples

Real-world.

  • 1 ln(e) = 1 because e¹ = e
  • 2 ln(1) = 0 because e⁰ = 1
  • 3 Finding the half-life of a radioactive substance using ln(2)
Key Fact

ln(e) = 1, ln(1) = 0, ln(eˣ) = x, e^(ln x) = x