• Nov 6th 2011, 06:13 AM
ChinaPanda
If x is a vector,and center it on the origin,but what dose the formula (x.1=0) mean?I am puzzled about why there is a point symbol behind vector x,and what does 1 mean?
I really appreciate your help!(Nod) The image below is the original text
Attachment 22683
• Nov 6th 2011, 06:20 AM
Moo
Hello,

Common notation for the scalar product.
• Nov 6th 2011, 06:32 AM
ChinaPanda
hi,can you speak in detail? My english is very poor,and can you give me a example? thank you very much
• Nov 6th 2011, 06:35 AM
ChinaPanda
You mean the point symbol means scalar product?but 1 means a vector that each element equals to 1?
• Nov 6th 2011, 06:36 AM
ChinaPanda
Quote:

Originally Posted by Moo
Hello,

Common notation for the scalar product.

You mean the point symbol means scalar product?but 1 means a vector that each element equals to 1?
• Nov 6th 2011, 06:38 AM
Moo
Quote:

Originally Posted by ChinaPanda
You mean the point symbol means scalar product?but 1 means a vector that each element equals to 1?

Yes, 1 stands for $\displaystyle \begin{pmatrix} 1\\1\\ \vdots \\ 1\end{pmatrix}$

This scalar product will actually give the sum of x's components.

duibuqi, wo bu hui shuo zhongwen shuxue :D
• Nov 6th 2011, 06:45 AM
ChinaPanda
Yes, 1 stands for $\displaystyle \begin{pmatrix} 1\\1\\ \vdots \\ 1\end{pmatrix}$