3.I 7C7 \mathrm{C} \quad

Linear Mathematics
Part IB, 2001

Determine the dimension of the subspace WW of R5\mathbb{R}^{5} spanned by the vectors

(12211),(42262),(45311),(54051)\left(\begin{array}{r} 1 \\ 2 \\ 2 \\ -1 \\ 1 \end{array}\right),\left(\begin{array}{r} 4 \\ 2 \\ -2 \\ 6 \\ -2 \end{array}\right),\left(\begin{array}{l} 4 \\ 5 \\ 3 \\ 1 \\ 1 \end{array}\right),\left(\begin{array}{r} 5 \\ 4 \\ 0 \\ 5 \\ -1 \end{array}\right)

Write down a 5×55 \times 5 matrix MM which defines a linear map R5R5\mathbb{R}^{5} \rightarrow \mathbb{R}^{5} whose image is WW and which contains (1,1,1,1,1)T(1,1,1,1,1)^{T} in its kernel. What is the dimension of the space of all linear maps R5R5\mathbb{R}^{5} \rightarrow \mathbb{R}^{5} with (1,1,1,1,1)T(1,1,1,1,1)^{T} in the kernel, and image contained in WW ?