# Numerical linear algebra (pseudoinverse of a matrix)

Let $A$ be the matrix:

$$\left(\begin{matrix} \alpha I_{n} \\ \beta I_{n} \end{matrix}\right)$$

where $\alpha,\beta\in\Bbb C$ are not both zero. Derive (a) the (reduced) QR factorization of $A$ and (b) the pseudoinverse of $A$.

Any help for the second question about pseudoinverse ?