?狽ﾌ計算

$3$\displaystyle{ {\sum }\limits_{ k=1 }^{n}1=n }$

$3$\displaystyle{{\sum }\limits_{ k=1 }^{n}k=\frac{\hspace{2} n $ n+1 $ \hspace{2}}{\hspace{2}2\hspace{2}}}$

$3$\displaystyle{{\sum }\limits_{ k=1 }^{n} {k}^{2} =\frac{\hspace{2} n $ n+1 $ $ 2n+1 $ \hspace{2}}{\hspace{2}6\hspace{2}}}$

$3$\displaystyle{{\sum }\limits_{ k=1 }^{n} {k}^{3} =\frac{\hspace{2} {n}^{2}{ $ n+1 $ }^{2} \hspace{2}}{\hspace{2}4\hspace{2}}}$

[し]
[さ行]
[索引トップ]