Problem:
Determine the value of m so that the vectors u=[4, -2, 6] and v=[6, m, 9] are:
a) Parallel
b) Perpendicular
Answers: a) -3
b) 39
Comments:
Please help me!
Hi !
If two vectors are parallel, there exists a real number x, different to 0, such that :
So seeing that and , can you set up a relation between -2 and m ?
------------------------------
Now, if two vectors are perpendicular, this means that the dot product is 0.
For two vectors : and , their dot product is :
So here, what is the dot product of u and v ? Deduce the value of m ?
This is exactly what you have to do
For this fancy math text, see this section : http://www.mathhelpforum.com/math-help/latex-help/, especially this thread : http://www.mathhelpforum.com/math-he...-tutorial.html
Moo, do you mind helping with one more? I posted it a short while back and I didn't understand the reply because the person was using techniques that I haven't even studied yet.
http://www.mathhelpforum.com/math-he...blem-help.html