データ分析 2023年度 ex03notebookB の問題の解答†
和の記号に関する復習†
A0a†
\begin{aligned}
\sum_{n=1}^{4}x_n &= x_1 + x_2 + x_3 + x_4 \\
&= 10 + 20 + 30 + 40 = 100\\
\sum_{n=5}^{8}x_n &= x_5 + x_6 + x_7 + x_8\\
&= 50 + 60 + 70 + 80 = 260
\end{aligned}
A0b†
\[ (\mbox{与式}) = x_1^2 + x_2^2 + x_3^2 = 100+400+900 = 1400
\]
A0c†
\begin{aligned}
(\mbox{与式}) &= \sum_{n=1}^{4}x_n + \sum_{n=1}^{4}\pi = 100 + (\pi + \pi + \pi + \pi) = 100+4\pi
\end{aligned}
A0d†
\[ (\mbox{与式}) = 2\sum_{n=1}^{4} x_n = 2\times 100 = 200
\]
A0e†
\begin{aligned}
(\mbox{与式}) = a\sum_{n=1}^{4}x_n + \sum_{n=1}^{4}b = 100a + 4b
\end{aligned}
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