# Homework Help: QM - Spin operator conjugate question

1. Nov 5, 2011

### QMQuestions2

1. The problem statement, all variables and given/known data

Okay so I've got a question I really need answered first up! If I have a 2x1 matrix for Psi, is Psi* a 1x2 matrix with all the 'i's turned to '-i's?

Now onto the actual question - http://imgur.com/3ucb4" [Broken] - part b only

2. Relevant equations

http://imgur.com/bcEm3" [Broken]

(Sorry to URL everything)

3. The attempt at a solution

http://imgur.com/FW0dP" [Broken]

What did I do wrong?

Last edited by a moderator: May 5, 2017
2. Nov 5, 2011

### Unto

Simply have the 2 x 2 matrix of Sx operate on the state v, then multiply your new 2 x 2 matrix with the conjugate of v.

And yes the conjugate of v is a transpose matrix with the i's all different.

3. Nov 5, 2011

### QMQuestions2

Isn't that what I did? v is a 2x1 matrix. When I multiply Sx with v I'm left with a 2x1 matrix, not a 2x2.

Sx times v = v

v* times v = 2

Integral = infinity