cpusspuss

In mathematics, the Nth harmonic number is defined to be 1 + 1/2 + 1/3 + 1/4 + ... + 1/N. So, the first harmonic number is 1, the second is 1.5, the third is 1.83333... and so on. Assume that  n is an integer variable whose value is some positive integer N. Assume also that  hn is a  double variable whose value is the Nth harmonic number. Write an expression whose value is the (N+1)th harmonic number.

Why is the answer:
hn + 1/(n+1)
incorrect?

(foldl (λ (n z) (+ z (/ 1.0 n))) 0 (range 1 (+ n 1)))