# Math Help - scalar triple product, check.

1. ## scalar triple product, check.

Given these vectors
$
\begin{array}{l}
\vec u = 2\hat i - \hat j + \hat k \\
\vec v = 3\hat i + \hat j - 2\hat k \\
\vec w = 3\hat i + 2\hat j \\
\end{array}
$

Find $\vec u \bullet (\vec v \times \vec w)$

When I calculate this I get 17 however the answer in the text is given as being 14.

2. Originally Posted by Craka

Given these vectors
$
\begin{array}{l}
\vec u = 2\hat i - \hat j + \hat k \\
\vec v = 3\hat i + \hat j - 2\hat k \\
\vec w = 3\hat i + 2\hat j \\
\end{array}
$

Find $\vec u \bullet (\vec v \times \vec w)$

When I calculate this I get 17 however the answer in the text is given as being 14.
I get 17 too. Perhaps we're both making the same mistake .....

3. Cheers. Glad to know I don't make mistakes all the time