Geoff's Line length given Co-ordinates problem

[jazzygeoff]

Hi all,

I wonder if someone can fill in the working for this problem?
I need to find length of the straight line between two points A and B on a graph.

The coordinates are (p,q) and (q,p).

AB is then:- sqrt ((q-p)^2 + (p-q)^2)

The answer in the book is:- sqrt (2(p-q)^2)

What is the working inbetween???? I can't get that result!!
Sorry if my maths typing is not very good!

Geoff

 

[pka]

Please note that (p−q)=−(q−p).
If we square both sides then they must be equal:
[(p−q)]<SUP>2</SUP>=[−(q−p)]<SUP>2</SUP>
√[2(p−q)<SUP>2</SUP>]

 

[jazzygeoff]

Wow thanks for that! 7 minutes for a reply!

I really appreciate it! By the way, how do you do the cool little sqrt and ^2 characters? I'm new to this message board.

Thanks again,
Geoff

 

[Gene]

The magic is in
( t y p e d w i t h no spaces )
x² = x < s u p > 2 < / s u p >
You can also use
x₂ = x < s u b > 2 < / s u b >

 

[stapel]

You can usually get the same effect by inserting an empty "bold". For instance:

. . . . .x²

...is formatted as:

. . . . .x²

...which I got to display in the line above by typing as follows:

. . . . .x²

See? :wink:

Eliz.