@@ 235,10 235,10 @@
\begin{itemize}
\item Everyone now has $S_1$, $S_2$, $\dots$, $S_k$: \pause
\begin{align*}
- S_1 &= \sum_{j=1}^k c_j + x_1 \sum_{j=1}^k a_{(j,1)} + x_1^2 \sum_{j=1}^k a_{(j,2)} + \cdots + x_1^{k-1} \sum_{j=1}^k a_{(j,2)} \\
- S_1 &= \sum_{j=1}^k c_j + x_2 \sum_{j=1}^k a_{(j,1)} + x_2^2 \sum_{j=1}^k a_{(j,2)} + \cdots + x_2^{k-1} \sum_{j=1}^k a_{(j,2)} \\
+ S_1 &= \sum_{j=1}^k c_j + x_1 \sum_{j=1}^k a_{(j,1)} + x_1^2 \sum_{j=1}^k a_{(j,2)} + \cdots + x_1^{k-1} \sum_{j=1}^k a_{(j,k-1)} \\
+ S_1 &= \sum_{j=1}^k c_j + x_2 \sum_{j=1}^k a_{(j,1)} + x_2^2 \sum_{j=1}^k a_{(j,2)} + \cdots + x_2^{k-1} \sum_{j=1}^k a_{(j,k-1)} \\
&\vdots \\
- S_k &= \sum_{j=1}^k c_j + x_k \sum_{j=1}^k a_{(j,1)} + x_k^2 \sum_{j=1}^k a_{(j,2)} + \cdots + x_k^{k-1} \sum_{j=1}^k a_{(j,2)}
+ S_k &= \sum_{j=1}^k c_j + x_k \sum_{j=1}^k a_{(j,1)} + x_k^2 \sum_{j=1}^k a_{(j,2)} + \cdots + x_k^{k-1} \sum_{j=1}^k a_{(j,k-1)}
\end{align*} \pause
\item These are $k$ points all on the same $k-1$ degree polynomial:
\begin{equation*}
@@ 253,17 253,17 @@
coefficients and constant term of it with a little linear algebra: \pause
\begin{equation*}
\begin{bmatrix}
- 1 & x_1 & x_1^2 & \cdots & x_1^k \\
- 1 & x_2 & x_2^2 & \cdots & x_2^k \\
+ 1 & x_1 & x_1^2 & \cdots & x_1^{k-1} \\
+ 1 & x_2 & x_2^2 & \cdots & x_2^{k-1} \\
\vdots & & & \ddots \\
- 1 & x_k & x_k^2 & \cdots & x_k^k
+ 1 & x_k & x_k^2 & \cdots & x_k^{k-1}
\end{bmatrix}
\begin{bmatrix}
\sum_{j=1}^k c_j \\
\sum_{j=1}^k a_{(j,1)} \\
\sum_{j=1}^k a_{(j,2)} \\
\vdots \\
- \sum_{j=1}^k a_{(j,2)}
+ \sum_{j=1}^k a_{(j,k-1)}
\end{bmatrix} =
\begin{bmatrix}
S_1 \\
@@ 279,10 279,10 @@
\begin{equation*}
\text{RREF}\left(
\begin{bmatrix}
- 1 & x_1 & x_1^2 & \cdots & x_1^k & S_1 \\
- 1 & x_2 & x_2^2 & \cdots & x_2^k & S_2 \\
+ 1 & x_1 & x_1^2 & \cdots & x_1^{k-1} & S_1 \\
+ 1 & x_2 & x_2^2 & \cdots & x_2^{k-1} & S_2 \\
\vdots & & & \ddots \\
- 1 & x_k & x_k^2 & \cdots & x_k^k & S_k
+ 1 & x_k & x_k^2 & \cdots & x_k^{k-1} & S_k
\end{bmatrix}
\right)
\end{equation*}