\[\boxed{\mathbf{676\ (676).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\]
\[Время,\ затраченное\ \] \[на\ выполнение\ дом.\ задания\ (ч).\] |
\[0\] | \[1\] | \[2\] | \[3\] | \[4\] |
---|---|---|---|---|---|
\[Частота\] | \[1\] | \[6\] | \[8\] | \[5\] | \[3\] |
\[Относительная\ частота,\ \%\] | \[4,3\] | \[26,1\] | \[34,8\] | \[21,7\] | \[13,1\] |
\[2)\ (0 + 1 \cdot 6 + 2 \cdot 8 + 3 \cdot 5 + 4 \cdot 3)\ :\]
\[:23 = 2,13\ (ч).\]
\[3)\ Мода\ равна\ 2\ ч.\]
\[\boxed{\mathbf{676.\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ b_{4} = 9;\ \ b_{6} = 25\ \ \]
\[b_{5}^{2} = b_{4} \cdot b_{6}\ \]
\[b_{5} = \sqrt{b_{4}b_{6}} = \sqrt{9 \cdot 25} =\]
\[= 3 \cdot 5 = 15\]
\[или\ \ \ \]
\[b_{5} = - \sqrt{9 \cdot 25} = - 15.\]
\[Ответ:\ b_{5} = \pm 15.\]
\[2)\ b_{19} = - 3;\ \ b_{21} = - 12\ \]
\[b_{20} = \pm \sqrt{b_{19}b_{21}} =\]
\[= \pm \sqrt{- 3 \cdot ( - 12)} = \pm \sqrt{36} = \pm 6\]
\[Ответ:\ b_{20} = \pm 6.\]
\[3)\ b_{16} = 2;\ \ b_{18} = 10\]
\[b_{17} = \pm \sqrt{b_{16} \cdot b_{18}} = \pm \sqrt{2 \cdot 10} =\]
\[= \pm \sqrt{20} = \pm 2\sqrt{5}.\]
\[Ответ:\ b_{17} = \pm 2\sqrt{5}.\]