I did this one the way I did a previous problem like this but came up with a completely incorrect answer

the question is:

vector a = (2,1,0) and vector b = (-1,6,1) find a vector perpendicular to both.

:)

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- Jan 11th 2011, 09:59 AMcoloradofind a vector perpendicular to both vector a and vector b
I did this one the way I did a previous problem like this but came up with a completely incorrect answer

the question is:

vector a = (2,1,0) and vector b = (-1,6,1) find a vector perpendicular to both.

:) - Jan 11th 2011, 10:04 AMdwsmith
$\displaystyle \displaystyle ||a\times b||=\begin{vmatrix}i&j&k\\2&1&0\\-1&6&1\end{vmatrix}=\mbox{normal vector}$

- Jan 11th 2011, 10:06 AMcolorado
how about using dot product? haven't got to cross product yet

- Jan 11th 2011, 10:07 AMdwsmith
The dot product produces a scalar not a vector.

- Jan 11th 2011, 10:08 AMdwsmith
- Jan 11th 2011, 10:10 AMAckbeet
You could use the dot product by setting up a system of two equations in three unknowns. That is, your unknown vector is r=(x,y,z). Set the dot product of r with both your initial vectors equal to zero, and solve the resulting system.

- Jan 11th 2011, 10:10 AMcolorado
no, haven't gotten to that point

- Jan 11th 2011, 10:13 AMcolorado
- Jan 11th 2011, 10:17 AMmr fantastic