# I am stuck at a simple trigonometry problem again

• July 24th 2012, 08:50 AM
mariusg
I am stuck at a simple trigonometry problem again
I have a simple question again:

I have this problem:

Given the points P(2,0,0). Q(4,3,-2) and R(-2,0,5) Find the coordinates for point S so that PQRS creates a parallelogram.

What i have tried is this:

Found the vector QP and the vector QR and then found S = WP + QR and that gave me [-9, -6, 5] and this does not conform with the answer in the textbook at all which is (-4,-3,7)
• July 24th 2012, 08:51 AM
mariusg
Re: I am stuck at a simple trigonometry problem again
Oops i found it, i offcourse have to add the vector to the point Q to find the point
• July 24th 2012, 09:19 AM
Plato
Re: I am stuck at a simple trigonometry problem again
Quote:

Originally Posted by mariusg
Given the points P(2,0,0). Q(4,3,-2) and R(-2,0,5) Find the coordinates for point S so that PQRS creates a parallelogram.
answer in the textbook at all which is (-4,-3,7)

You could note that $\[\overrightarrow {QP} = \left\langle { - 2, - 3,2} \right\rangle$
So $\overrightarrow {QP}+\left\langle { - 2, 0,5} \right\rangle=\left\langle { - 4,-3,7} \right\rangle$