Logarithms

The logarithm is the inverse of the exponential, which is why it solves for exponents.

• y = bˣ has inverse y = log_b x.
• log(ab) = log a + log b; log(a/b) = log a − log b; log(aⁿ) = n·log a.
• Change of base: log_b a = log a / log b.
• log x is defined only for x > 0.

• Logarithm — the exponent to which a base must be raised.