Kevin,
I am not asking for the calculator to be radically modified.
Yes, I understand and agree it's good, perhaps even esential, to
understand the concept behind what you are asking the calculator
to do.
I did realise that -8^(1/3) is -2.
That's not really the point.
The calculator should be there really for when the numbers get
more awkward.
In the original emails, sometimes the exponent was (4/3)
sometimes (3/4).
With a negative number, as you know, that makes quite a
difference.
The cube root of a negative number is reasonable--something that
the calculator might be able to provide.
Now, the work around is, take off the "-" cube root it and stick
the "-" back on.
I am not asking for imaginary numbers, (I), that's going perhaps
a little far.
I also could not really think of an example where you might have
to preceed a minus with a left bracket.
The inability to do so was just something that came up while
messing around raising negative numbers to various powers.
It is arithmetically quite legal though, so it might be nice to
have.
And as you mention it, a^-b to raise "a" to the power -"b".
Though using the 1/a^b is a decent substitute.
I have actually hardly ever used the calculator, but when I have
I reckon it's quite good.
Not done proper math though for something like 25 years.
Regards,
Steve.
----- Original Message -----
From: Kevin Chao <[EMAIL PROTECTED]
To: "'Stephen'" <[EMAIL PROTECTED]>,"'BrailleNote List'"
<[email protected]
Date sent: Thu, 15 May 2008 13:50:56 -0700
Subject: RE: [Braillenote] Calculator issues that ought to be
addressed
Steve,
Very valid points, I think that these issues are also important
being a huge
math fan. But where is the limit of the calculator, shall we ask
for the
ability to do matrices and inverse matrices; be able to graph
parabolic,
cubic, sinusoidal functions and other curves?
I will run through the suggestions that you provided and provide
my
comments.
1. When an attempt is made to do an opperation which the
calculator can not
perform, it should produce an appropriate message as well as the
error
beep--(rather than 0).
This is true, but let's say someone tries, "-4^-2" and you get
the answer
of 0 followed by an error tone if speech is on/request. The most
important
thing before using a calculator is being able to conceptualize
the
mathematical problem and to be able to do it by hand or if it
isn't
possible, know why it isn't possible. For example, let's
rewrite the
expression without a negaitve exponent, it would be, "-(1/4)^2"
yielding an
answer of 1/16. KeyPlus has an issue with the negative sign
before the "4"
and produces a 0 instead of the correct answer as well as an
error tone. If
someone has this as expression they must answer and they write
the answer as
0 because that is what the calculator provided, I would then
suggest Math
Tutorial as this shows a lack of understanding of the
mathematical concept
and a dependacy on the calculator.
2. At the moment, you can not follow the left bracket with a
minus sign.
Although this does not matter for a number, you might want to
minus a
further bracketed expression.
I feel this should be possible.
This is possible with things moving around properly and
parenthese being
placed at the right locations. Can you provide an example and I
will turn it
around?
3.
This will need checking by someone who knows maths.
It seems reasonable for the calculator to struggle with even
roots of
negative numbers.
For example how will it cope with square root or fourth root of
-1?
However, should it be able to deal with odd roots?
For example a cube root of -8 is -2.
First, it should be math not maths. -1^(1/2) is where we get into
imaginary
numbers and I think is beyond the ability of KeyPlus. Again, this
goes back
to being able to conceptualize the mathematical problem, if we
know that
-28(1/3) is -2 then why pull out the calculator?
^1/2 = square root
^1/3 = cube root
Most of the above issues are issues of math skills not an issue
with a
calculator.
Kevin
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
Stephen
Sent: Thursday, May 15, 2008 1:09 PM
To: BrailleNote List
Subject: [Braillenote] Calculator issues that ought to be
addressed
Hi,
There are three things which I believe need dealing with in the
calculator.
The first two have been forwarded by an HW contact to the
technical folks,
the third hasn't.
These are:-
1. When an attempt is made to do an opperation which the
calculator can not
perform, it should produce an appropriate message as well as the
error
beep--(rather than 0).
2. At the moment, you can not follow the left bracket with a
minus sign.
Although this does not matter for a number, you might want to
minus a
further bracketed expression.
I feel this should be possible.
3.
This will need checking by someone who knows maths.
It seems reasonable for the calculator to struggle with even
roots of
negative numbers.
For example how will it cope with square root or fourth root of
-1?
However, should it be able to deal with odd roots?
For example a cube root of -8 is -2.
Regards,
Steve.
----------------------------------------------------------
"seek ye first the kingdom of God, and his righteousness;"
(Matthew 6:33 AV)
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