## chrisplusian one year ago Linear algebra question dealing with transpose

1. chrisplusian

I can't figure out how to input matrices here but $b = \left[\begin{matrix}1 \\ 1 \\ -1 \end{matrix}\right]$

2. chrisplusian

i figured it out..... find $b^{T}b$

3. chrisplusian

what I got was a three by three $\left[\begin{matrix}1 & 1 & -1\\ 1 & 1 & -1\\ -1 & -1 & 1\end{matrix}\right]$

4. chrisplusian

just wanted to check and see if this is correct

5. dan815

it should say b*b^T if u got that

6. dan815

3 by 1 matrix * 1by 3 matrix = 3 by 3 matrix, ^--------^---- these inner dimensions have to be equal, that is a way to check if solution exists

7. dan815

rows by columns

8. chrisplusian

Sorry that is correct it should have said b*b^T

9. chrisplusian

would that be correct for b*b^T ?

10. dan815

yes its right

11. chrisplusian

thank you

12. dan815

okay but btw

13. dan815

if u do b^t * b you will get 3

14. chrisplusian

Yeah I actually did that problem first, for some reason I was second guessing myself on this part though

15. dan815

ah okay