Gram Schmidt F7A198
1. **Problem Statement:**
Given vectors $v_1 = \begin{bmatrix}1 \\ 1 \\ 0\end{bmatrix}$, $v_2 = \begin{bmatrix}1 \\ 0 \\ 1\end{bmatrix}$, and $v_3 = \begin{bmatrix}0 \\ 1 \\ 1\end{bmatrix}$, we want to find an orthogonal set of vectors using the Gram-Schmidt process.
2. **Formula and Rules:**
The Gram-Schmidt process constructs an orthogonal set $\{u_1, u_2, u_3\}$ from $\{v_1, v_2, v_3\}$ as follows:
$$
u_1 = v_1
$$
$$
u_k = v_k - \sum_{j=1}^{k-1} \mathrm{proj}_{u_j}(v_k) \quad \text{for } k=2,3
$$
where the projection is
$$
\mathrm{proj}_{u_j}(v_k) = \frac{v_k \cdot u_j}{u_j \cdot u_j} u_j
$$
3. **Step 1: Compute $u_1$**
$$
u_1 = v_1 = \begin{bmatrix}1 \\ 1 \\ 0\end{bmatrix}$$
4. **Step 2: Compute $u_2$**
Calculate the projection of $v_2$ onto $u_1$:
$$v_2 \cdot u_1 = 1 \times 1 + 0 \times 1 + 1 \times 0 = 1$$
$$u_1 \cdot u_1 = 1^2 + 1^2 + 0^2 = 2$$
$$\mathrm{proj}_{u_1}(v_2) = \frac{1}{2} \begin{bmatrix}1 \\ 1 \\ 0\end{bmatrix} = \begin{bmatrix}0.5 \\ 0.5 \\ 0\end{bmatrix}$$
Then,
$$
u_2 = v_2 - \mathrm{proj}_{u_1}(v_2) = \begin{bmatrix}1 \\ 0 \\ 1\end{bmatrix} - \begin{bmatrix}0.5 \\ 0.5 \\ 0\end{bmatrix} = \begin{bmatrix}0.5 \\ -0.5 \\ 1\end{bmatrix}$$
5. **Step 3: Compute $u_3$**
Calculate projections of $v_3$ onto $u_1$ and $u_2$:
$$v_3 \cdot u_1 = 0 \times 1 + 1 \times 1 + 1 \times 0 = 1$$
$$u_1 \cdot u_1 = 2$$
$$\mathrm{proj}_{u_1}(v_3) = \frac{1}{2} \begin{bmatrix}1 \\ 1 \\ 0\end{bmatrix} = \begin{bmatrix}0.5 \\ 0.5 \\ 0\end{bmatrix}$$
Next,
$$v_3 \cdot u_2 = 0 \times 0.5 + 1 \times (-0.5) + 1 \times 1 = 0.5$$
$$u_2 \cdot u_2 = 0.5^2 + (-0.5)^2 + 1^2 = 0.25 + 0.25 + 1 = 1.5$$
$$\mathrm{proj}_{u_2}(v_3) = \frac{0.5}{1.5} \begin{bmatrix}0.5 \\ -0.5 \\ 1\end{bmatrix} = \frac{1}{3} \begin{bmatrix}0.5 \\ -0.5 \\ 1\end{bmatrix} = \begin{bmatrix}0.1667 \\ -0.1667 \\ 0.3333\end{bmatrix}$$
Finally,
$$\nu_3 = v_3 - \mathrm{proj}_{u_1}(v_3) - \mathrm{proj}_{u_2}(v_3) = \begin{bmatrix}0 \\ 1 \\ 1\end{bmatrix} - \begin{bmatrix}0.5 \\ 0.5 \\ 0\end{bmatrix} - \begin{bmatrix}0.1667 \\ -0.1667 \\ 0.3333\end{bmatrix} = \begin{bmatrix}-0.6667 \\ 0.6667 \\ 0.6667\end{bmatrix}$$
6. **Result:**
The orthogonal set is
$$
u_1 = \begin{bmatrix}1 \\ 1 \\ 0\end{bmatrix}, \quad \nu_2 = \begin{bmatrix}0.5 \\ -0.5 \\ 1\end{bmatrix}, \quad \nu_3 = \begin{bmatrix}-0.6667 \\ 0.6667 \\ 0.6667\end{bmatrix}$$
These vectors are mutually orthogonal and span the same subspace as the original vectors.