Re: [Phys-L] Halfway point ???

["Donald Polvani" <dgpolvani@verizon.net>]

On 4/4/15 at 10:48 AM John Denker wrote:

> On 04/04/2015 07:27 AM, Donald Polvani wrote:
> the harmonic mean

> 1/x_HM = (1/x_1 + 1/x_2)/2  or  x_HM = 1/(1/x_1 + 1/x_2)/2
>                                                         ^^^^ The last
factor there is either a typo or an abuse of the notation.  The rule is than
in an expression such as ...

Yes, what I meant was x_HM = 1/((1/x_1 + 1/x_2)/2)

However, in the same message, John Denker also wrote:

> Therefore the reciprocal of a / b is 1 / b * a or 1 / (a / b) ... not
simply 1 / a / b.

The first part of this (1 / b *a) is also either a typo or an abuse of the
notation, since the reciprocal of a / b is b / a  or (1 / a) * b.

It would be much easier for authors to check their work and spot problems
like the above, if the email system (I use MS Outlook) permitted one to
write math symbols and equations in "textbook style" as can be done, for
example, in MS Word.  Does anyone know of an "easy" way to type math
equations in MS Outlook, so we don't have to put so many parentheses and
other ad hoc devices on expressions to make the meaning clear?  Or, if such
a procedure exists, would it mean that others on the list, not using MS
Outlook, would only see gibberish where the equations were?