Find a vector perpendicular to $Oy$ axis. Knowing that $v\cdot v_1=8$ and $v\cdot v_2=-3$, where $v_1=(3,1,-2)$ and $v_2=(-1,1,1)$
Calculate a vector that is perpendicular to Oy axis.
1
$\begingroup$
linear-algebra
-
3Are you aware of the practice of accepting answers to your question? (See [this meta question](http://meta.math.stackexchange.com/questions/3399).) – 2012-07-27
-
0Yes, but I don´t understand your commentaire. Was I rude with someone here. If I was, I´m sorry about it. – 2012-07-28
1 Answers
1
ley $v=(x,y,z)$ perpendicular to $OY$ axis means that $v*(0,1,0)=0$ $v*v_1=3*x+1*y-2*z=8$
$v*v_2=-1*x+1*y+1*z=-3$
$v*(0,1,0)=0 -->y=0$
so $3*x-2*z=8$
$-x+z=-3$ from second $z=-3+x$ put into first one
$3*x-2*(-3+x)=8$
$x=2$ and $z=-1$ so we have
$v=(2,0,-1)$
-
0my friend i am happy that could help you,just please consider advices from other people and accept their answers,it is rule of this website ok?it is friendly advice – 2012-07-27
-
0Thanks dato. I will consider this in the future. – 2012-07-28