Originally Posted by

**elitethut** Hi,

This is my first post on the forum, but I have been reading this forum for at least 2 years now. It has always been very useful to read some of the posts you guys make.

However, now, it seems like I can't solve my problem simply by reading the forum...I would need a little extra help.

Here is how it goes:

*(Note: Let bold letters be vectors)*

I know that **u**=(u1,u2,u3), **v**=(v1,v2,v3) and **w**=(w1,w2,w3)

Let A=$\displaystyle \begin{array}{ccc}u1&u2&u3\\v1&v2&v3\\w1&w2&w3\end {array}$

I have to prove that:

*(Note: Let u,v and w, be vectors)*

det(A) $\displaystyle \leq$ $\displaystyle \parallel u \parallel \parallel v \parallel \parallel w \parallel $

I tried to replace the norm of **u** times norm of **v** times norm of **w** by its equivalent using their values (u1,u2,u3), (v1,v2,v3), (w1,w2,w3).

Hence, $\displaystyle \parallel u \parallel = \sqrt{u \cdot u}$ ...

But then, all I got was a huge equation and the strange impression that I am not even close from doing the right thing...

Anyone could help me head in the right direction ?

Thanks a lot !