Harmonic mean

Harmonic means are a type of mean. It is the number of values divided by the reciprocal of the values. If there are formula_1 numbers formula_2, then the harmonic mean of these numbers are
formula_3
Out of the geometric mean and arithmetic mean, the harmonic mean is usually the smallest.
Example.
Let's find the harmonic mean of 2,4 and 5. There are three numbers so we will be dividing three. The reciprocals of the numbers are formula_4, formula_5 and formula_6. If we add the reciprocals we get formula_7. If we divide three by this number, the result is formula_8 (approximately 3.157894737)