Liczby odwrotne to takie liczby, których iloczyn wynosi 1.
[tex]a) \sqrt{\frac{3}{5}} * \sqrt{15} = \sqrt{\frac{3}{5}*15} = \sqrt{9} = 3[/tex]
liczba odwrotna to [tex]\frac{1}{3}[/tex], bo:
[tex]3*\frac{1}{3} = \frac{3}{3} =1[/tex]
[tex]b)\sqrt{5\frac{1}{4}} * \sqrt{\frac{3}{7}} = \sqrt{\frac{21}{4}*\frac{3}{7}} = \sqrt{\frac{49}{4}} = \frac{7}{2}[/tex]
liczba odwrotna to [tex]\frac{2}{7}[/tex], bo:
[tex]\frac{7}{2} * \frac{2}{7} = \frac{14}{14} = 1[/tex]
[tex]c) \sqrt[3]{25} * \sqrt[3]{40} = \sqrt[3]{25*40} = \sqrt[3]{1000} = 10[/tex]
liczba odwrotna to [tex]\frac{1}{10}[/tex], bo:
[tex]10 * \frac{1}{10} =\frac{10}{10} = 1[/tex]
[tex]d) \sqrt[3]{75} * \sqrt[3]{45} = \sqrt[3]{75*45} = \sqrt[3]{3375} = 15[/tex]
liczba odwrotna to [tex]\frac{1}{15}[/tex], bo:
[tex]15 * \frac{1}{15} = \frac{15}{15} = 1[/tex]
[tex]e)\frac{\sqrt{128} }{\sqrt{512} } = \sqrt{\frac{128}{512}} = \sqrt{\frac{1}{4}} = \frac{1}{2}[/tex]
liczba odwrotna to [tex]\frac{2}{1}[/tex], czyli 2, bo:
[tex]\frac{1}{2} *2= \frac{2}{2} =1[/tex]
[tex]f) \frac{\sqrt{216} }{\sqrt{192} } = \sqrt{\frac{216}{192} } = \sqrt{\frac{9}{8} }[/tex]
liczba odwrotna to [tex]\frac{1}{\sqrt{\frac{9}{8} } }[/tex], bo:
[tex]\sqrt{\frac{9}{8} } * \frac{1}{\sqrt{\frac{9}{8} } } = \frac{\sqrt{\frac{9}{8}}}{\sqrt{\frac{9}{8}}} =\sqrt{\frac{9}{8}:\frac{9}{8} } = \sqrt{\frac{9}{8}*\frac{8}{9}} = \sqrt{\frac{72}{72} } = \sqrt{1} = 1[/tex]
[tex]g)\sqrt{1\frac{9}{16} } : \sqrt{\frac{225}{256} } = \sqrt{\frac{25}{16}*\frac{256}{225} } = \sqrt{\frac{16}{9} } = \frac{4}{3}[/tex]
liczba odwrotna to [tex]\frac{3}{4}[/tex], bo:
[tex]\frac{4}{3} * \frac{3}{4} = \frac{12}{12} = 1[/tex]
[tex]h) \sqrt{1\frac{1}{2} } : \sqrt{1\frac{5}{27} } = \sqrt{\frac{3}{2}*\frac{27}{32}}= \sqrt{\frac{81}{64} } = \frac{9}{8}[/tex]
liczba odwrotna to [tex]\frac{8}{9}[/tex], bo:
[tex]\frac{9}{8} *\frac{8}{9} = \frac{72}{72} = 1[/tex]