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Old April 21st 12, 06:13 PM posted to rec.radio.amateur.antenna
John S John S is offline
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First recorded activity by RadioBanter: May 2011
Posts: 550
Default Be careful when using Excel

On 4/21/2012 5:06 AM, Helmut Wabnig wrote:
On Fri, 8 May 2009 18:36:08 +0200, "Antonio Vernucci"
wrote:

I think this message can be of interest for those using Excel for antenna
calculations.

Write in one cell: =(-A1^2 + 8) Note: the exponent of A1 is 2 (and not
2+8=10) because Excel performs squaring before summing

Write in another cell: =(8 - A1^2)

They look pretty much the same

But give A1 any non-zero value and see what happen.

73

Tony I0JX
Rome, Italy


That's funny.
I would improve for clarity by putting spaces between

Write in one cell: =(- A1^2 + 8) .......... (result xxx(censored)
Write in another cell: =(8 - A1^2).............(result x(censored))

The result is same a yours, despite the spaces.
You may also enter negative numbers in A1 and also
decimal numbers, everytime a surprise.


Another Microsoft blunder?


w.


No. Excel's parser can't always tell whether you want to negate A1
before squaring or not. Don't be lazy; group with parentheses when in doubt.

-(A1^2) + 8
works exactly the same as
8 - (A1^2)