5.4 Logs facts

Log facts:

$$log_b(x \times y) = log_b(x) + log_b(y).$$

$$log_b\left(\frac{x}{y}\right) = log_b(x) - log_b(y).$$

The log of product is the sum of the logs.

$$log_b(x^m) = m\,log_b(x).$$

$$log_b(0) = -\infty.$$

log_b(1) = 0.

$$log_b(b^x) = x log_b(b) = x \times 1 = x.$$

So that log undoes to the power x.