# URGENT! Very easy Vector exercise!

• May 5th 2008, 12:51 AM
Akuma666
URGENT! Very easy Vector exercise!

It's supposed to be a parallelogram.

O (0;0)
P (6;8)
Q (9;14)

Vector OP and OQ are parallelogram sides.
I need this parallelogram diagonals and their edge-top coordinates.
And if possible, then drawing too!

It's very easy, all you need is one edge-top to find!

First diag : OP + OQ =
Sec. diag : OP - OQ =

Thanks!!
• May 5th 2008, 02:32 AM
topsquark
Quote:

Originally Posted by Akuma666

It's supposed to be a parallelogram.

O (0;0)
P (6;8)
Q (9;14)

Vector OP and OQ are parallelogram sides.
I need this parallelogram diagonals and their edge-top coordinates.
And if possible, then drawing too!

It's very easy, all you need is one edge-top to find!

First diag : OP + OQ =
Sec. diag : OP - OQ =

Thanks!!

Try looking at it this way. The opposite sides in a parallelogram are equal and parallel. So if the last point in your parallelogram is R then we know that vector OP and vector QR are equal. Similarly vectors OQ and PR are equal.

-Dan
• May 5th 2008, 03:39 AM
Akuma666

I have this drawing in my notebook right now and well it looks SO weird, i'd really feel more comfortable if I'd knew it is correct one, this simple exercise is actually very important.

Could you please or anyone else make the drawing and give me the vector numbers? (Thinking)

Thanks.
• May 5th 2008, 03:45 AM
topsquark
Quote:

Originally Posted by Akuma666

I have this drawing in my notebook right now and well it looks SO weird, i'd really feel more comfortable if I'd knew it is correct one, this simple exercise is actually very important.

Could you please or anyone else make the drawing and give me the vector numbers? (Thinking)

Thanks.

Quote:

Originally Posted by Akuma666
O (0;0)
P (6;8)
Q (9;14)

Well the vector OP is the directed line segment from (0, 0) to (6, 8), so it has the vector coordinates <6, 8>.

Since OP = QR, we can base the vector <6, 8> at point Q and travel 6 units to the right and 8 units up to get point R.

-Dan
• May 5th 2008, 03:47 AM
james_bond
$\vec{OA}=\vec{OP}+\vec{OQ}=(15,22)\qquad \vec{QP}=\vec{OP}-\vec{OQ}=(-3,-6)$
• May 5th 2008, 03:48 AM
Akuma666
Thank you both very much! I'm very glad someone helped me with this. ^_^
• May 5th 2008, 03:49 AM
topsquark
Quote:

Originally Posted by james_bond
$\vec{OP}+\vec{OQ}=(15,22)\qquad \vec{OP}-\vec{OQ}=(-3,-6)$

(Chuckles)
That diagram is not only very large, but the parallelogram is so squished that it is almost impossible to make out any details! Try reducing the size and changing the scale of the x and y axis a bit.

-Dan