# Math Help - polynomials spanning P2

1. ## polynomials spanning P2

Does the folloowing set of polynomials span $P_2$?
${t^2+2t-1, t^2-1}$
When I formed the coefficient matrix I got
$
\left[ {\begin{array}{ccc}
1 & 1 & 0 \\
2 & 0 & 0 \\
-1 & 0 & 0 \\

\end{array} } \right]

$

$
\left[ {\begin{array}{cc}
1 & 1 \\
2 & 0 \\
-1 & 0 \\

\end{array} } \right]

$

Is one right/wrong or better?

2. Originally Posted by Jskid
Does the folloowing set of polynomials span $P_2$?
${t^2+2t-1, t^2-1}$
When I formed the coefficient matrix I got
$
\left[ {\begin{array}{ccc}
1 & 1 & 0 \\
2 & 0 & 0 \\
-1 & 0 & 0 \\

\end{array} } \right]

$

$
\left[ {\begin{array}{cc}
1 & 1 \\
2 & 0 \\
-1 & 0 \\

\end{array} } \right]

$

Is one right/wrong or better?

What do you need any matrix for? The space $P_2$ is of dimension 3, and you're given only 2 vectors...

Tonio

3. Where did that third column come from? You were given two vectors so the matrix should have two columns.