I've recently noticed that Excel flies in the face of standard scientific,
mathematical and engineering convention in the calculation of powers for
numbers that are then multiplied by a negative.

The convention of mathematics, "BIMDAS" (or similar acronyms), states that
_I_ndices (or powers, or exponents), should be calculated before
_M_ultiplication. Because of this, the following is accepted as correct:

-3^2 = -9.

This is because it is the equivalent of (-1) * 3^2 = -1 * 9 = -9

However, Excel chooses to recognise this as (-3)^2 = 9.

This error is particularly problematic when doing algebraic computations in
such a tool as Mathematica and then copying the result into Excel in input
form. That is,

-x^2 - -A1^2
- -A1^2
(Mathematica) (Mathematica with reference substituted) (Excel)

To correct the error, one must manually change it to: -(A1^2)

QUESTIONS
1: Why does Excel have this convention!
2: Is there any way to change it/make is more convenient?

I've only recently noticed this (which is quite scary to think how many
errors I may have made in the past!)

Thanks for your time,

Cheers,
Peter

Why? Because that's the way they wrote it. And no, there's no way to change
this. You must write your Excel formulas to a suit the way Excel does the
calculations.

On Mon, 21 Feb 2005 19:47:02 -0800, "Atreides" <atreides1AThotmailD0Tcom
wrote:

I've recently noticed that Excel flies in the face of standard scientific,
mathematical and engineering convention in the calculation of powers for
numbers that are then multiplied by a negative.

The convention of mathematics, "BIMDAS" (or similar acronyms), states that
_I_ndices (or powers, or exponents), should be calculated before
_M_ultiplication. Because of this, the following is accepted as correct:

-3^2 = -9.

This is because it is the equivalent of (-1) * 3^2 = -1 * 9 = -9

However, Excel chooses to recognise this as (-3)^2 = 9.

This error is particularly problematic when doing algebraic computations in
such a tool as Mathematica and then copying the result into Excel in input
form. That is,

-x^2 - -A1^2
- -A1^2
(Mathematica) (Mathematica with reference substituted) (Excel)

To correct the error, one must manually change it to: -(A1^2)

QUESTIONS
1: Why does Excel have this convention!
2: Is there any way to change it/make is more convenient?

I've only recently noticed this (which is quite scary to think how many
errors I may have made in the past!)

Thanks for your time,

Cheers,
Peter

Why? Because that's the way they wrote it.

Why is the sky blue? Because. ;)

I was hoping for something more informative than this. e.g.
1. This convention was considered more intuitive to the majority of expected
users.
2. Computer programmers live in their own world and have their own
conventions.
3. Other...

And no, there's no way to change this.

Perhaps this should be included in the next version of Excel. Some other
options can be changed with regards to the calculations (by going to "Tools",
"Options", "Calculation"). This would be quite a useful feature.

Thanks
Peter

Maybe is skewed. I was taught that -3^2=9, and not -9. The integer used
is -3, not -1*3. You may think I was taught wrong. I submit to you I was not
taught in this country, rather, I grew up in Europe. Could it be that Excel
had some European programmers....

Roy
"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
Why? Because that's the way they wrote it.

Why is the sky blue? Because. ;)

I was hoping for something more informative than this. e.g.
1. This convention was considered more intuitive to the majority of
expected
users.
2. Computer programmers live in their own world and have their own
conventions.
3. Other...

And no, there's no way to change this.

Perhaps this should be included in the next version of Excel. Some other
options can be changed with regards to the calculations (by going to
"Tools",
"Options", "Calculation"). This would be quite a useful feature.

Thanks
Peter

Maybe is skewed. I was taught that -3^2=9, and not -9. The integer used
is -3, not -1*3. You may think I was taught wrong. I submit to you I was not
taught in this country, rather, I grew up in Europe. Could it be that Excel
had some European programmers....

This could have something to do with it.

However, the convention -x^2 == -(x^2) is not negotiable when you are
working with algebra. If you are dealing with real numbers, then writing -x^2
would be pointless if -x^2 really means (-x)^2 == ( -1)^2 * (x)^2 = x^2

Therefore, if the "European convention" you mention holds, then -x^2 == x^2.
(!)

So then, -x^2 should be taken as -(x^2), to mean the opposite of the square
of x, and to differentiate it from simplifying to x^2.

Cheers,
Peter

**PS**

The post that Alan mentioned (http://tinyurl.com/5t69s) is good reading on
this topic. Apparently the issue cost someone $2000 in time and effort to
resolve!

The convention as I've learnt it is that the power operator is only applied
to the argument immediately under the indice. So for instance:
2 * 3^2 = 2 * 9 = 18 AND
(2 * 3)^2 = 6^2 = 36
(2 * 3)^2 = 2^2 * 3 ^ 2 = 4 * 9 = 36

Therefore, if the negative is meant to be included in the power, it should
be included in brackets. So then:
-3^2 = -1 * 3^2 AND
(-3)^2 = 9
(-3)^2 = (-1 * 3)^2 = (-1)^2 * (3)^2 = 1 * 9 = 9

"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
Maybe is skewed. I was taught that -3^2=9, and not -9. The integer used
is -3, not -1*3. You may think I was taught wrong. I submit to you I was
not
taught in this country, rather, I grew up in Europe. Could it be that
Excel
had some European programmers....

This could have something to do with it.

However, the convention -x^2 == -(x^2) is not negotiable when you are
working with algebra. If you are dealing with real numbers, then
writing -x^2
would be pointless if -x^2 really means (-x)^2 == ( -1)^2 * (x)^2 =
x^2

Therefore, if the "European convention" you mention holds, then -x^2 ==
x^2.
(!)



I'll add my comment - Yes, this is correct, and this is what I was taught
(many moons ago). However, I see you point as well and find myself more
agreeable with it than my own 'paradigm', if you will. Thanks!




So then, -x^2 should be taken as -(x^2), to mean the opposite of the
square
of x, and to differentiate it from simplifying to x^2.

Cheers,
Peter

**PS**

The post that Alan mentioned (http://tinyurl.com/5t69s) is good reading on
this topic. Apparently the issue cost someone $2000 in time and effort to
resolve!

The convention as I've learnt it is that the power operator is only
applied
to the argument immediately under the indice. So for instance:
2 * 3^2 = 2 * 9 = 18 AND
(2 * 3)^2 = 6^2 = 36
(2 * 3)^2 = 2^2 * 3 ^ 2 = 4 * 9 = 36

Therefore, if the negative is meant to be included in the power, it should
be included in brackets. So then:
-3^2 = -1 * 3^2 AND
(-3)^2 = 9
(-3)^2 = (-1 * 3)^2 = (-1)^2 * (3)^2 = 1 * 9 = 9

Royman101 wrote...
Maybe is skewed. I was taught that -3^2=9, and not -9. The integer
used
is -3, not -1*3. You may think I was taught wrong. I submit to you I
was not
taught in this country, rather, I grew up in Europe. Could it be that
Excel
had some European programmers....

I have a few German language math texts that show equations that
clearly show they follow exponentiation before negation operator
precedence. Perhaps it may be unreasonable to extrapolate from that
that Germany follows the same operator precedence convention as the US,
but I'd be willing to bet that was so.

"Atreides" <atreides1AThotmailD0Tcom wrote...
....
I was hoping for something more informative than this. e.g.
1. This convention was considered more intuitive to the majority of
expected users.
....

Perhaps now, but not necessarily back when spreadsheets made their big debut
in the mid 1980s. FWLIW, this is COBOL's sign convention, and maybe it
wasn't unreasonable for Microsoft's original Excel programmers to decide
that it'd be a good idea to follow COBOL operator precedence.

Then again, Lotus 123 follows standard mathematical conventions and gives
exponentiation higher precedence than unary minus (sign change), so
Microsoft's original programmers gave Excel a different operator precedence
convention than the leading spreadsheet on the market back when they were
developing the original version of Excel. That alone makes it VERY LIKELY
this was a design screw-up, but once made it can't be unmade because it'd
break existing formulas relying on current operator precedence.

If you really believe you want to read about this, follow these archived
threads.

http://groups-beta.google.com/group/...214f129ec55664

http://groups-beta.google.com/group/...fc5978cbbd95a8


And no, there's no way to change this.

Perhaps this should be included in the next version of Excel. Some other
options can be changed with regards to the calculations (by going to
"Tools", "Options", "Calculation"). This would be quite a useful feature.

Don't count on this happening. Excel's formula parser, in which its operator
precedence is implemented, seems to be one of the oldest, most myopically
designed bits of code in all of Excel. If Microsoft hasn't made any
fundamental changes since Excel 4 (3D referencing within .XLW workbooks),
over a decade ago, why would you believe they have any inclination to fix
this any time soon?

Also, flipping operator precedence on the fly would require a different
formula parser of every possible operator precedence combination. That'd add
considerable bulk to the Excel .EXE - not a good thing.

Who would would possibly know why they did it this way? What's the point of
wasting time speculating about WHY?

You have a problem to solve. I would think your time would be better spent
on that aspect. Fundamentally, you need to add parentheses to an expression
like -X^2 so it becomes -(X^2).

It is VERY unlikely this will be changed. It could "break" existing
spreadsheet formulas that have been written to accommodate Excel's
calculation order.


"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
Why? Because that's the way they wrote it.

Why is the sky blue? Because. ;)

I was hoping for something more informative than this. e.g.
1. This convention was considered more intuitive to the majority of
expected
users.
2. Computer programmers live in their own world and have their own
conventions.
3. Other...

And no, there's no way to change this.

Perhaps this should be included in the next version of Excel. Some other
options can be changed with regards to the calculations (by going to
"Tools",
"Options", "Calculation"). This would be quite a useful feature.

Thanks
Peter

Who would would possibly know why they did it this way? What's the point of
wasting time speculating about WHY?

When confronted with something that is so incredibly against convention (and
that I have somehow not noticed for the last 10 or so years), it pulls
terribly at my curiosity.

Also, to increase my understanding of computers and calculating program.

You have a problem to solve. I would think your time would be better spent
on that aspect. Fundamentally, you need to add parentheses to an expression
like -X^2 so it becomes -(X^2).

Yes, this is the obvious fix. However, I have been (and will continue to)
copy formulas from Mathematica (in Input Form, which is almost identical to
Excel format, except for issues like this). If I could avoid all past and
future manual changes to be spreadsheets, this would be incredibly valuable.

But alas.

Here's to checking assumptions...

Cheers,
Peter

"Atreides" <atreides1AThotmailD0Tcom wrote in message
...

I've recently noticed that Excel flies in the face of standard
scientific, mathematical and engineering convention in the
calculation of powers for numbers that are then multiplied by a
negative.

The convention of mathematics, "BIMDAS" (or similar acronyms),
states
that _I_ndices (or powers, or exponents), should be calculated
before
_M_ultiplication. Because of this, the following is accepted as
correct:

-3^2 = -9.

This is because it is the equivalent of (-1) * 3^2 = -1 * 9 = -9

However, Excel chooses to recognise this as (-3)^2 = 9.

This error is particularly problematic when doing algebraic
computations in such a tool as Mathematica and then copying the
result into Excel in input form. That is,

-x^2 - -A1^2
- -A1^2
(Mathematica) (Mathematica with reference substituted)
(Excel)

To correct the error, one must manually change it to: -(A1^2)

QUESTIONS
1: Why does Excel have this convention!
2: Is there any way to change it/make is more convenient?

I've only recently noticed this (which is quite scary to think how
many errors I may have made in the past!)

Thanks for your time,

Cheers,
Peter


Hi Peter,

See this thread for a *very* comprehensive discussion on the topic:

http://groups.google.co.nz/groups?hl...umbus. rr.com

Or this (same thing but shorter URL):

http://tinyurl.com/5t69s


Enjoy!

Alan.

-3^2 is the same as -3*-3 which equals 9 not -9

At least that's what I was taught over 60 years ago.

--
Ken Russell


Remove yourhat to reply by e-mail
..

"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
I've recently noticed that Excel flies in the face of standard scientific,
mathematical and engineering convention in the calculation of powers for
numbers that are then multiplied by a negative.

The convention of mathematics, "BIMDAS" (or similar acronyms), states that
_I_ndices (or powers, or exponents), should be calculated before
_M_ultiplication. Because of this, the following is accepted as correct:

-3^2 = -9.

This is because it is the equivalent of (-1) * 3^2 = -1 * 9 = -9

However, Excel chooses to recognise this as (-3)^2 = 9.

This error is particularly problematic when doing algebraic computations
in
such a tool as Mathematica and then copying the result into Excel in input
form. That is,

-x^2 - -A1^2
- -A1^2
(Mathematica) (Mathematica with reference substituted) (Excel)

To correct the error, one must manually change it to: -(A1^2)

QUESTIONS
1: Why does Excel have this convention!
2: Is there any way to change it/make is more convenient?

I've only recently noticed this (which is quite scary to think how many
errors I may have made in the past!)

Thanks for your time,

Cheers,
Peter

But then Ken, what reason would one have for writing:

-x^2

if it really simplifies down to -x * -x = x^2?

How would one write the opposite of the square of x?

Cheers,
Peter


"Ken Russell" wrote:

-3^2 is the same as -3*-3 which equals 9 not -9

At least that's what I was taught over 60 years ago.

--
Ken Russell


Remove yourhat to reply by e-mail
..

"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
I've recently noticed that Excel flies in the face of standard scientific,
mathematical and engineering convention in the calculation of powers for
numbers that are then multiplied by a negative.

The convention of mathematics, "BIMDAS" (or similar acronyms), states that
_I_ndices (or powers, or exponents), should be calculated before
_M_ultiplication. Because of this, the following is accepted as correct:

-3^2 = -9.

This is because it is the equivalent of (-1) * 3^2 = -1 * 9 = -9

However, Excel chooses to recognise this as (-3)^2 = 9.

This error is particularly problematic when doing algebraic computations
in
such a tool as Mathematica and then copying the result into Excel in input
form. That is,

-x^2 - -A1^2
- -A1^2
(Mathematica) (Mathematica with reference substituted) (Excel)

To correct the error, one must manually change it to: -(A1^2)

QUESTIONS
1: Why does Excel have this convention!
2: Is there any way to change it/make is more convenient?

I've only recently noticed this (which is quite scary to think how many
errors I may have made in the past!)

Thanks for your time,

Cheers,
Peter

Doesn't -(x^2) satisfy -9?

--
Ken Russell


Remove yourhat to reply by e-mail
..

"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
But then Ken, what reason would one have for writing:

-x^2

if it really simplifies down to -x * -x = x^2?

How would one write the opposite of the square of x?

Cheers,
Peter


"Ken Russell" wrote:

-3^2 is the same as -3*-3 which equals 9 not -9

At least that's what I was taught over 60 years ago.

--
Ken Russell


Remove yourhat to reply by e-mail
..

"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
I've recently noticed that Excel flies in the face of standard
scientific,
mathematical and engineering convention in the calculation of powers
for
numbers that are then multiplied by a negative.

The convention of mathematics, "BIMDAS" (or similar acronyms), states
that
_I_ndices (or powers, or exponents), should be calculated before
_M_ultiplication. Because of this, the following is accepted as
correct:

-3^2 = -9.

This is because it is the equivalent of (-1) * 3^2 = -1 * 9 = -9

However, Excel chooses to recognise this as (-3)^2 = 9.

This error is particularly problematic when doing algebraic
computations
in
such a tool as Mathematica and then copying the result into Excel in
input
form. That is,

-x^2 - -A1^2
- -A1^2
(Mathematica) (Mathematica with reference substituted)
(Excel)

To correct the error, one must manually change it to: -(A1^2)

QUESTIONS
1: Why does Excel have this convention!
2: Is there any way to change it/make is more convenient?

I've only recently noticed this (which is quite scary to think how many
errors I may have made in the past!)

Thanks for your time,

Cheers,
Peter

Doesn't -(x^2) satisfy -9?

Yes, according to your convention, you would have to write -(x^2). So
consider the two systems we could have:

1. x^2 the opposite of which is -x^2
2. x^2 the opposite of which is -(x^2)

System number one (which, in my experience, is standard in maths, science
and engineering textbooks) makes more sense to me. Indices or powers have
precedence over multiplication.

Consider graphs of parabolas. According to your definition, the graphs:

y = x^2

AND

y = -x^2

would be the same graph. However, in my experience, eveyone knows that y =
x^2 is a "U" shape while y = -x^2 is an "upsidedown-U" shape.

Would you agree?

Cheers,
Peter





"Ken Russell" wrote:


--
Ken Russell


Remove yourhat to reply by e-mail
..

"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
But then Ken, what reason would one have for writing:

-x^2

if it really simplifies down to -x * -x = x^2?

How would one write the opposite of the square of x?

Cheers,
Peter


"Ken Russell" wrote:

-3^2 is the same as -3*-3 which equals 9 not -9

At least that's what I was taught over 60 years ago.

--
Ken Russell


Remove yourhat to reply by e-mail
..

"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
I've recently noticed that Excel flies in the face of standard
scientific,
mathematical and engineering convention in the calculation of powers
for
numbers that are then multiplied by a negative.

The convention of mathematics, "BIMDAS" (or similar acronyms), states
that
_I_ndices (or powers, or exponents), should be calculated before
_M_ultiplication. Because of this, the following is accepted as
correct:

-3^2 = -9.

This is because it is the equivalent of (-1) * 3^2 = -1 * 9 = -9

However, Excel chooses to recognise this as (-3)^2 = 9.

This error is particularly problematic when doing algebraic
computations
in
such a tool as Mathematica and then copying the result into Excel in
input
form. That is,

-x^2 - -A1^2
- -A1^2
(Mathematica) (Mathematica with reference substituted)
(Excel)

To correct the error, one must manually change it to: -(A1^2)

QUESTIONS
1: Why does Excel have this convention!
2: Is there any way to change it/make is more convenient?

I've only recently noticed this (which is quite scary to think how many
errors I may have made in the past!)

Thanks for your time,

Cheers,
Peter

I am a simple man who bows to your superior knowledge. At least all my
maths teachers are dead now :-)

Cheers,
Ken Russell


Remove yourhat to reply by e-mail
..

"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
Doesn't -(x^2) satisfy -9?

Yes, according to your convention, you would have to write -(x^2). So
consider the two systems we could have:

1. x^2 the opposite of which is -x^2
2. x^2 the opposite of which is -(x^2)

System number one (which, in my experience, is standard in maths, science
and engineering textbooks) makes more sense to me. Indices or powers have
precedence over multiplication.

Consider graphs of parabolas. According to your definition, the graphs:

y = x^2

AND

y = -x^2

would be the same graph. However, in my experience, eveyone knows that y =
x^2 is a "U" shape while y = -x^2 is an "upsidedown-U" shape.

Would you agree?

Cheers,
Peter





"Ken Russell" wrote:


--
Ken Russell


Remove yourhat to reply by e-mail
..

"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
But then Ken, what reason would one have for writing:

-x^2

if it really simplifies down to -x * -x = x^2?

How would one write the opposite of the square of x?

Cheers,
Peter


"Ken Russell" wrote:

-3^2 is the same as -3*-3 which equals 9 not -9

At least that's what I was taught over 60 years ago.

--
Ken Russell


Remove yourhat to reply by e-mail
..

"Atreides" <atreides1AThotmailD0Tcom wrote in message
...
I've recently noticed that Excel flies in the face of standard
scientific,
mathematical and engineering convention in the calculation of powers
for
numbers that are then multiplied by a negative.

The convention of mathematics, "BIMDAS" (or similar acronyms),
states
that
_I_ndices (or powers, or exponents), should be calculated before
_M_ultiplication. Because of this, the following is accepted as
correct:

-3^2 = -9.

This is because it is the equivalent of (-1) * 3^2 = -1 * 9 = -9

However, Excel chooses to recognise this as (-3)^2 = 9.

This error is particularly problematic when doing algebraic
computations
in
such a tool as Mathematica and then copying the result into Excel in
input
form. That is,

-x^2 - -A1^2
- -A1^2
(Mathematica) (Mathematica with reference substituted)
(Excel)

To correct the error, one must manually change it to: -(A1^2)

QUESTIONS
1: Why does Excel have this convention!
2: Is there any way to change it/make is more convenient?

I've only recently noticed this (which is quite scary to think how
many
errors I may have made in the past!)

Thanks for your time,

Cheers,
Peter