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Jun 28th, 2006, 10:23 PM
#1
Thread Starter
Lively Member
Distance formula (find 1 end point)
Hi,
I know the distance formula is
d = Sqrt( ((x2 - x1) ^2) + ((y2 - y1) ^ 2))
If I have values for distance, and y2 and y1, how do I determine x2 and x1?
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Jun 29th, 2006, 07:20 AM
#2
Addicted Member
Re: Distance formula (find 1 end point)
You just don´t. You have to have X1 or X2. At least one of these two values has to be known, otherwise X1 can be any value and X2 will be easily found (or interchange X1 and X2).
Rui
...este projecto dos Deuses que os homens teimam em arruinar...
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Jun 29th, 2006, 03:13 PM
#3
Fanatic Member
Re: Distance formula (find 1 end point)
You don't have enough information to get x2 and x1. With the information provided, you can get x2 - x1, but that's it. You have a single equation with 2 unknowns ==> infinite number of solutions. You need a 2nd equation.
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Sep 7th, 2008, 07:21 AM
#4
New Member
Re: Distance formula (find 1 end point)
how to write a vbscript of distance formula
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Sep 8th, 2008, 04:19 AM
#5
Re: Distance formula (find 1 end point)
Your post title says "find 1 end point" but your problem statement is asking for the x coordinate of both points instead of the x and y coordinate of a single point. If you know one point's location and the distance, there are still an infinite number of answers, but instead they lie on a circle. Using the setup you've given, the points may lie on parallel (horizontal) lines.
Not sure if that's helpful, though maybe it is for terminology.
The time you enjoy wasting is not wasted time.
Bertrand Russell
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Sep 9th, 2008, 06:01 AM
#6
Re: Distance formula (find 1 end point)
The only quantity that's unambiguously determined is the positive difference of the x coordinates,
|x2 - x1| = +Sqr[d2 - (y2 - y1)2]
where the vertical bars mean absolute value.
You can't even say whether x2 > x1 or x2 < x1
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