- #1
CFDFEAGURU
- 783
- 10
Hello all,
In the book "A First Course in General Relativity" by Schutz (1985 Edition) in chapter 2 there is a problem concerning summation that has me confused.
Note: This is not homework, just an interest of mine.
The given quantities are:
A = (5,0,-1,-6)
B = (0,-2,4,0)
C = [ 1 0 2 3
5 -2 -2 0
4 5 2 -2
-1 -2 -2 0 ]
Find:
A (super alpha) * C (sub alpha, beta); for all beta.
As usual, I apologize for not using LaTex but I can never get it to work right.
My attempt.
The only sum is on alpha because it is the only repeated upper and lower index. I should end up with a set of 4 numbers.
I followed the example given on page 41 of the book and applied it to this problem, but I got all 4 numbers wrong.
For the first value I calculated:
(1)*(5) + (0)*(0) + (2)*(-1) + (3)*(-6) = -15
The answer is given as (7, 1, 26, 17).
Any help on what I am doing wrong would be greatly appreciated.
Thanks
Matt
In the book "A First Course in General Relativity" by Schutz (1985 Edition) in chapter 2 there is a problem concerning summation that has me confused.
Note: This is not homework, just an interest of mine.
The given quantities are:
A = (5,0,-1,-6)
B = (0,-2,4,0)
C = [ 1 0 2 3
5 -2 -2 0
4 5 2 -2
-1 -2 -2 0 ]
Find:
A (super alpha) * C (sub alpha, beta); for all beta.
As usual, I apologize for not using LaTex but I can never get it to work right.
My attempt.
The only sum is on alpha because it is the only repeated upper and lower index. I should end up with a set of 4 numbers.
I followed the example given on page 41 of the book and applied it to this problem, but I got all 4 numbers wrong.
For the first value I calculated:
(1)*(5) + (0)*(0) + (2)*(-1) + (3)*(-6) = -15
The answer is given as (7, 1, 26, 17).
Any help on what I am doing wrong would be greatly appreciated.
Thanks
Matt