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Minus 0
By Michael Brooker on Monday, November 19, 2001 - 05:54 pm:

Can there be a minus nought? A negative number times a positive number is a negative number. So 0, which is usually defined as positive, multiplied by any negative number equals minus 0. Or does it?

Michael Brooker

By Emma McCaughan on Monday, November 19, 2001 - 06:04 pm:

Let's think about temperature, where we use negative numbers quite a lot.
-1°C means 1 degree below freezing.
-2°C means 2 degrees below freezing.
So what does -0°C mean?

You can think about non-negative numbers, as opposed to positive numbers. I would say that 0 is not a positive number, but it is a non-negative number.

By Tristan Marshall on Tuesday, November 20, 2001 - 01:32 pm:

By convention, we say 0 is neither positive nor negative. This is sometimes called the law of trichotomy - every real number is either positive, negative, or zero.

By Dave Sheridan on Wednesday, November 21, 2001 - 02:26 pm:

Another way to think about it is that -n is what we need to add to n to get 0. For example, when we say the temperature is -2, we mean if the temperature were to raise by 2 degrees (ie we add 2), it would be equal to zero.

If you take this definition, then -0 is what we would need to add to 0 in order to get 0. So -0 is actually the same as 0.

Does that make sense?

-Dave

By Michael Brooker on Tuesday, January 08, 2002 - 02:26 pm:

Yes, I did expect -0 and 0 to be the same, but some weird things do happen in maths. Studying quadratic curves has helped my understanding.

Thank you,

Michael

By Taimur Farooqi on Saturday, May 25, 2002 - 03:58 pm:

There is no such thing as -0

By Brad Rodgers on Sunday, May 26, 2002 - 01:21 am:

Sure there is!

-1.0 = -0.

It's just that -0 = 0, which seems sort of counterintuitive.

Brad