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I have the following:
a-b=X
I need one single formula (that uses only addition, substraction, multiplication or division) where if X is a positive number the result will be 1 and if X is a negative number the result will be -1 or 0
Is this possible?
Thanx in advance!
nik
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How about |X| ÷ X?
That formula will give 1 if X is positive, -1 if X is negative and won't work if X is 0.
Edit: |X| ≡ abs (X). But you figured that out anyway.
Why did the vector cross the road?
It wanted to be normal.
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How about |X| ÷ X?
That formula will give 1 if X is positive, -1 if X is negative and won't work if X is 0.
Excuse my ignorance, but if i do X ÷ X I get 1 if X is positive, but if X is negative I still get 1, unless |X| means absolute value which I am not sure it will be recognized on a computer.
I appreciate your help
nik
Last edited by nikad (2006-01-21 12:07:02)
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I will try to compute the absolute value somehow, you ruuuuuuuuuuuuuule!
nik
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Here you go:
x³ / ((x²)^9)^(1/6)
That will work but I don't know how you would do it in computer language.
x³ / √(x^6)
That might be easier.
I am at an age where I have forgotten more than I remember, but I still pretend to know it all.
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Wouldn't it be simpler to just have x/√x² if you're doing it that way?
Why did the vector cross the road?
It wanted to be normal.
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Some people......just kidding. Of course it would, but I am not the sharpest knife in the drawer you know?
I am at an age where I have forgotten more than I remember, but I still pretend to know it all.
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Hehe, sorry. I'll try to go easy on you from now on.
Why did the vector cross the road?
It wanted to be normal.
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Pour it on. I am a glutton for punishment. That is why I keep posting answers when I know that I will be corrected eventually.
I am at an age where I have forgotten more than I remember, but I still pretend to know it all.
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[x+abs(x)]/2x
positive = 1
negative = 0
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Assuming that you are programming this...
unless |X| means absolute value which I am not sure it will be recognized on a computer.
Absolute value is extremely easy to do on a computer. All it requires is to switch the very first bit of a signed number and then subtract that from the highest possible signed value. Most languages support an abs() function, but it also works if you just do: x = (unsigned int) x or something similar.
But if you're on a computer, the above isn't needed.
if (X < 0) return -1; return 1;
x³ / ((x²)^9)^(1/6)
That will work but I don't know how you would do it in computer language.
Pretty easy actually:
(x*x*x) / pow((pow(x, 18)), 1/6)
If your language doesn't support a power function, you can write it yourself, although doing non integral powers is a bit tricky. But, as I said, you don't need to do all this.
Last edited by Ricky (2006-01-21 20:35:20)
"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."
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