# [SOLVED]whit.a.6.1 Show that the plane H defined by:

#### karush

##### Well-known member
$\tiny{whit.a.6.1}$

Show that the plane H defined by:

$H=\left\{ \alpha_1\left[ \begin{array}{rrr}1\\1\\1\end{array} \right] +\alpha_2\left[\begin{array}{rrr}1\\-1\\0\end{array} \right] \textit{ Such that } \alpha_1,\ \alpha_1\in\mathbb{R}\right\} =\begin{bmatrix}a_1+a_2\\ a_1+a_2\\ a_1\end{bmatrix}$
$\text{rref}(H)=\left[ \begin{array}{cc|c} 1 & 0 & 0 \\ 0 & 1 & 0 \\0 & 0 & 0 \end{array} \right]$
ok I don't know what this answers

Last edited:

#### Country Boy

##### Well-known member
MHB Math Helper
What question are you trying to answer?

The fact that
$H=\left\{ \alpha_1\left[ \begin{array}{rrr}1\\1\\1\end{array} \right] +\alpha_2\left[\begin{array}{rrr}1\\-1\\0\end{array} \right] \textit{ Such that } \alpha_1,\ \alpha_1\in\mathbb{R}\right\}$
IS the same as
$\begin{bmatrix}a_1+a_2\\ a_1+a_2\\ a_1\end{bmatrix}$
should be obvious from the definitions of "scalar multiplication" and "addition of vectors".

Or are you trying to say that something is true about that plane? If so, what?

($\left[ \begin{array}{cc|c} 1 & 0 & 0 \\ 0 & 1 & 0 \\0 & 0 & 0 \end{array} \right]$ doesn't appear to have anything to do with this problem and "$\text{rref}(H)$" doesn't make sense because "H" is plane, not a matrix.)

• karush and topsquark

#### Country Boy

##### Well-known member
MHB Math Helper
It's odd that Karush "liked" my response but did not answer the questions I asked.

#### karush

##### Well-known member
What question are you trying to answer?

The fact that
$H=\left\{ \alpha_1\left[ \begin{array}{rrr}1\\1\\1\end{array} \right] +\alpha_2\left[\begin{array}{rrr}1\\-1\\0\end{array} \right] \textit{ Such that } \alpha_1,\ \alpha_1\in\mathbb{R}\right\}$
IS the same as
$\begin{bmatrix}a_1+a_2\\ a_1+a_2\\ a_1\end{bmatrix}$
should be obvious from the definitions of "scalar multiplication" and "addition of vectors".

Or are you trying to say that something is true about that plane? If so, what?

($\left[ \begin{array}{cc|c} 1 & 0 & 0 \\ 0 & 1 & 0 \\0 & 0 & 0 \end{array} \right]$ doesn't appear to have anything to do with this problem and "$\text{rref}(H)$" doesn't make sense because "H" is plane, not a matrix.)
that was shown in an example