QR Factorization of A: Simple Procedure

[rbwang1225]

Homework Statement

Find the QR factorization of A = {1, 1}, {-1, 1}

The Attempt at a Solution

I just don't know the procedure.
I know it means that I need find Q and R such that A=QR, Q be orthogonal, and R be upper triangular.
It may be solved by assign Q = {a, b},{c, d}, where $Q^TQ=1$
and P = {e, f}, {0, g}
But, as I run Mathematica, it gives me P that the left-down side entry is nonzero.
Is there any point that I misunderstood?
And is there any way to simplify the procedure?
P.S. Please forgive me that I don't know how to "type" a matrix.
Regards.

 

[sunjin09]

Q is obtained by Schmidt othnormalization, record the coefficients to get R.