[Math] Distance Formula in Three Dimensions

3dgeometry

The distance formula in 3-D space is defined as:

$$|P_1\, P_2| = \sqrt{(x_2- x_1)^2 + (y_2 -y_1)^2 + (z_2- z_1)^2}$$

My question is that if I have 2 points that have negative coordinates, do I have to use the absolute value on all the points?

For example my two points are $\,P(3, -2, -3)\,\,,\,\, Q(7,0,1)$

When I plug in the y and z values of P do I have to use positive 2 and positive 3?

Thanks in advance.

Best Answer

The formula is correct for all real numbers. You don't need absolute value. (Note that $-3$ and $1$ are $4$ units apart, not $2$.)

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