That's because the well known fact that e^e = inf. Therefore log(inf) = e. Ruby is probably rounding up e/2. Proof: the infinite series 1 + 1/2 +1/3! +... is k

That's because the well known fact that e^e = inf. Therefore log(inf) = e. Ruby is probably rounding up e/2. Proof: the infinite series 1 + 1/2 +1/3! +... is known to converge to e. Now arrange in binomials: (1+1/2)^e + (1/3!)^e + ... this is known to be larger than (1+1/2)^2 + ... = 1 + 1/2 + 1/4 + 1 + 2/3 + 1/9 + ..... But this infinite series contains the series that sums to 2 (1 + 1/2 + 1/4 +...) and so the series that sums to 3, etc. Then it is equal to the sum of all positive integers which is infinite. (This is a joke.)