HarmonicMean
Computes the harmonic mean of all elements in a container or in a sequence. The elements must be numbers.
Syntax

HarmonicMean(X)

X
is a vector, matrix, list, or set


HarmonicMean(expr, var, a, b)

expr
is an expression in one variablevar

var
is the variable inexpr

a
is the lower bound 
b
is the upper bound

Description
Computing the mean of a container
If X
is a nonempty container of numbers, then HarmonicMean(X)
is the harmonic mean of all elements in X
.
The following container types are supported:

vectors

the result is the mean of all components


matrices

the result is the mean of all entries


lists containing numbers

the result is the mean of all numbers


sets containing numbers

the result is the mean of all numbers

Typewise, the elements may be either real or complex, and the result is complex iff at least one of the elements is complex.
Computing the mean of a sequence
HarmonicMean(expr, var, a, b)
computes the harmonic mean of the expression expr
in one variable var
as var
takes all integer values from a
to b
(inclusively).
expr
must return a number.
Examples
Computing the mean of a container
HarmonicMean(❨5, 1, 2, 6, 3, 8, 4, 10, 2, 3❩)
2.85035629454 (=1200/421)
Computing the mean of a sequence
HarmonicMean(n^2 + 3⋅n + 1, n, 1, 100)
186.411917683