oktw says to #ysitd <licson>: Properties 1. log_a(xy) = log_a(x) + log_a(y) 2. log_a(x/y) = log_a(x) - log_a(y) 3. log_a(x^y) = y log_a(x) 4. log_b(x) = log_a(x) / log_a(b)