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9.5E:练习

  • Page ID
    204351
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    练习成就完美

    除以平方根

    在以下练习中,进行简化。

    示例\(\PageIndex{43}\)

    \(\frac{\sqrt{27}}{6}\)

    回答

    \(\frac{\sqrt{3}}{2}\)

    示例\(\PageIndex{44}\)

    \(\frac{\sqrt{50}}{10}\)

    示例\(\PageIndex{45}\)

    \(\frac{\sqrt{72}}{9}\)

    回答

    \(\frac{2\sqrt{2}}{3}\)

    示例\(\PageIndex{46}\)

    \(\frac{\sqrt{243}}{6}\)

    示例\(\PageIndex{47}\)

    \(\frac{2−\sqrt{32}}{8}\)

    回答

    \(\frac{1−2\sqrt{2}}{4}\)

    示例\(\PageIndex{48}\)

    \(\frac{3+\sqrt{27}}{9}\)

    示例\(\PageIndex{49}\)

    \(\frac{6+\sqrt{45}}{6}\)

    回答

    \(\frac{2+\sqrt{5}}{2}\)

    示例\(\PageIndex{50}\)

    \(\frac{10−\sqrt{200}}{20}\)

    示例\(\PageIndex{51}\)

    \(\frac{\sqrt{80}}{\sqrt{125}}\)

    回答

    \(\frac{4}{5}\)

    示例\(\PageIndex{52}\)

    \(\frac{\sqrt{72}}{\sqrt{200}}\)

    示例\(\PageIndex{53}\)

    \(\frac{\sqrt{128}}{\sqrt{72}}\)

    回答

    \(\frac{4}{3}\)

    示例\(\PageIndex{54}\)

    \(\frac{\sqrt{48}}{\sqrt{75}}\)

    示例\(\PageIndex{55}\)
    1. \(\frac{\sqrt{8x^6}}{2x^2}\)
    2. \(\frac{\sqrt{200m^5}}{98m}\)
    回答
    1. \(2x^2\)
    2. \(\frac{10m^2}{7}\)
    示例\(\PageIndex{56}\)
    1. \(\frac{\sqrt{10y^3}}{5y}\)
    2. \(\frac{\sqrt{108n^7}}{243n^3}\)
    示例\(\PageIndex{57}\)

    \(\frac{\sqrt{75r^3}}{108r}\)

    回答

    \(\frac{5r}{6}\)

    示例\(\PageIndex{58}\)

    \(\frac{\sqrt{196q^5}}{484q}\)

    示例\(\PageIndex{59}\)

    \(\frac{\sqrt{108p^{5}q^{2}}}{\sqrt{34p^{3}q^{6}}}\)

    回答

    \(\frac{3p\sqrt{102}}{17q^2}\)

    示例\(\PageIndex{60}\)

    \(\frac{\sqrt{98rs^{10}}}{\sqrt{2r^{3}s^{4}}}\)

    示例\(\PageIndex{61}\)

    \(\frac{\sqrt{320mn^{5}}}{\sqrt{45m^{7}n^{3}}}\)

    回答

    \(\frac{8n}{3m^3}\)

    示例\(\PageIndex{62}\)

    \(\frac{\sqrt{810c^{3}d^{7}}}{\sqrt{1000c^{5}d}}\)

    示例\(\PageIndex{63}\)

    \(\frac{\sqrt{98}}{14}\)

    回答

    \(\frac{\sqrt{2}}{2}\)

    示例\(\PageIndex{64}\)

    \(\frac{\sqrt{72}}{18}\)

    示例\(\PageIndex{65}\)

    \(\frac{5+\sqrt{125}}{15}\)

    回答

    \(\frac{1+\sqrt{3}}{3}\)

    示例\(\PageIndex{66}\)

    \(\frac{6−\sqrt{45}}{12}\)

    示例\(\PageIndex{67}\)

    \(\frac{\sqrt{96}}{\sqrt{150}}\)

    回答

    \(\frac{4}{5}\)

    示例\(\PageIndex{68}\)

    \(\frac{\sqrt{28}}{\sqrt{63}}\)

    示例\(\PageIndex{69}\)

    \(\frac{\sqrt{26y^7}}{2y}\)

    回答

    \(y^3\sqrt{13}\)

    示例\(\PageIndex{70}\)

    \(\frac{\sqrt{15x^3}}{\sqrt{3x}}\)

    合理化单项分母

    在以下练习中,对分母进行简化和合理化。

    示例\(\PageIndex{71}\)

    \(\frac{10}{\sqrt{6}}\)

    回答

    \(\frac{5\sqrt{6}}{3}\)

    示例\(\PageIndex{72}\)

    \(\frac{8}{\sqrt{3}}\)

    示例\(\PageIndex{73}\)

    \(\frac{6}{\sqrt{7}}\)

    回答

    \(\frac{6\sqrt{7}}{7}\)

    示例\(\PageIndex{74}\)

    \(\frac{4}{\sqrt{5}}\)

    示例\(\PageIndex{75}\)

    \(\frac{3}{\sqrt{13}}\)

    回答

    \(\frac{3\sqrt{13}}{13}\)

    示例\(\PageIndex{76}\)

    \(\frac{10}{\sqrt{11}}\)

    示例\(\PageIndex{77}\)

    \(\frac{10}{3\sqrt{10}}\)

    回答

    \(\frac{\sqrt{10}}{3}\)

    示例\(\PageIndex{78}\)

    \(\frac{2}{5\sqrt{2}}\)

    示例\(\PageIndex{79}\)

    \(\frac{4}{9\sqrt{5}}\)

    回答

    \(\frac{4\sqrt{5}}{45}\)

    示例\(\PageIndex{80}\)

    \(\frac{9}{2\sqrt{7}}\)

    示例\(\PageIndex{81}\)

    \(−\frac{9}{2\sqrt{3}}\)

    回答

    \(−\frac{3\sqrt{3}}{2}\)

    示例\(\PageIndex{82}\)

    \(−\frac{8}{3\sqrt{6}}\)

    示例\(\PageIndex{83}\)

    \(\sqrt{\frac{3}{20}}\)

    回答

    \(\frac{\sqrt{15}}{10}\)

    示例\(\PageIndex{84}\)

    \(\sqrt{\frac{4}{27}}\)

    示例\(\PageIndex{85}\)

    \(\sqrt{\frac{7}{40}}\)

    回答

    \(\frac{\sqrt{70}}{20}\)

    示例\(\PageIndex{86}\)

    \(\sqrt{\frac{8}{45}}\)

    示例\(\PageIndex{87}\)

    \(\sqrt{\frac{19}{175}}\)

    回答

    \(\frac{\sqrt{133}}{35}\)

    示例\(\PageIndex{88}\)

    \(\sqrt{\frac{17}{192}}\)

    合理化两项分母

    在以下练习中,通过合理化分母进行简化。

    示例\(\PageIndex{89}\)
    1. \(\frac{3}{3+\sqrt{11}}\)
    2. \(\frac{8}{1−\sqrt{5}}\)
    回答
    1. \(\frac{3(3−\sqrt{11})}{−2}\)
    2. \(−2(1+\sqrt{5})\)
    示例\(\PageIndex{90}\)
    1. \(\frac{4}{4+\sqrt{7}}\)
    2. \(\frac{7}{2−\sqrt{6}}\)
    示例\(\PageIndex{91}\)
    1. \(\frac{5}{5+\sqrt{6}}\)
    2. \(\frac{6}{3−\sqrt{7}}\)
    回答
    1. \(\frac{5(5−\sqrt{6})}{19}\)
    2. \(3(3+\sqrt{7})\)
    示例\(\PageIndex{92}\)
    1. \(\frac{6}{6+\sqrt{5}}\)
    2. \(\frac{5}{4−\sqrt{11}}\)
    示例\(\PageIndex{93}\)

    \(\frac{\sqrt{3}}{\sqrt{m}−\sqrt{5}}\)

    回答

    \(\frac{\sqrt{3}(\sqrt{m}+\sqrt{5})}{m−5}\)

    示例\(\PageIndex{94}\)

    \(\frac{\sqrt{5}}{\sqrt{n}−\sqrt{7}}\)

    示例\(\PageIndex{95}\)

    \(\frac{\sqrt{2}}{\sqrt{x}−\sqrt{6}}\)

    回答

    \(\frac{\sqrt{2}(\sqrt{x}+\sqrt{3})}{x−6}\)

    示例\(\PageIndex{96}\)

    \(\frac{\sqrt{7}}{\sqrt{y}+\sqrt{3}}\)

    示例\(\PageIndex{97}\)

    \(\frac{\sqrt{r}+\sqrt{5}}{\sqrt{r}−\sqrt{5}}\)

    回答

    \(\frac{(\sqrt{r}+\sqrt{5})^2}{r−5}\)

    示例\(\PageIndex{98}\)

    \(\frac{\sqrt{s}−\sqrt{6}}{\sqrt{s}+\sqrt{6}}\)

    示例\(\PageIndex{99}\)

    \(\frac{\sqrt{150x^{2}y^{6}}}{\sqrt{6x^{4}y^{2}}}\)

    回答

    \(\frac{5y^2}{x}\)

    示例\(\PageIndex{100}\)

    \(\frac{\sqrt{80p^{3}q}}{\sqrt{5pq^{5}}}\)

    示例\(\PageIndex{101}\)

    \(\frac{15}{\sqrt{5}}\)

    回答

    \(3\sqrt{5}\)

    示例\(\PageIndex{102}\)

    \(\frac{3}{5\sqrt{8}}\)

    示例\(\PageIndex{103}\)

    \(\sqrt{\frac{8}{54}}\)

    回答

    \(\frac{2\sqrt{3}}{9}\)

    示例\(\PageIndex{104}\)

    \(\sqrt{\frac{12}{20}}\)

    示例\(\PageIndex{105}\)

    \(\frac{3}{5+\sqrt{5}}\)

    回答

    \(\frac{3(5−\sqrt{5})}{20}\)

    示例\(\PageIndex{106}\)

    \(\frac{20}{4−\sqrt{3}}\)

    示例\(\PageIndex{107}\)

    \(\frac{\sqrt{2}}{\sqrt{x}−\sqrt{3}}\)

    回答

    \(\frac{\sqrt{2}(\sqrt{x}+\sqrt{3})}{x−3}\)

    示例\(\PageIndex{108}\)

    \(\frac{\sqrt{5}}{\sqrt{y}−\sqrt{7}}\)

    示例\(\PageIndex{109}\)

    \(\frac{\sqrt{x}+\sqrt{8}}{\sqrt{x}−\sqrt{8}}\)

    回答

    \(\frac{(\sqrt{x}+2\sqrt{2})^2}{x−8}\)

    示例\(\PageIndex{110}\)

    \(\frac{\sqrt{m}−\sqrt{3}}{\sqrt{m}+\sqrt{3}}\)

    日常数学

    示例\(\PageIndex{111}\)

    在 250 英尺高度飞行的飞机上掉落补给包。 简化\(\sqrt{\frac{250}{16}}\)以确定补给套件到达地面需要多少秒。

    回答

    \(\frac{5\sqrt{10}}{4}\)

    示例\(\PageIndex{112}\)

    一架在 1200 英尺高度飞行的飞机上,一枚照明弹掉入海中。 简化\(\sqrt{\frac{1200}{16}}\)以确定耀斑到达海洋需要多少秒。

    写作练习

    示例\(\PageIndex{113}\)
    1. 简化\(\sqrt{\frac{27}{3}}\)并解释您的所有步骤。
    2. 简化\(\sqrt{\frac{27}{5}}\)并解释您的所有步骤。
    3. 为什么两种简化平方根的方法不同?
    回答

    答案会有所不同。

    示例\(\PageIndex{114}\)
    1. 在不使用计算器的情况下\(\frac{1}{1.414}\)使用长除法进行近似值\(\frac{1}{\sqrt{2}}\)
    2. 合理化捐\(\frac{1}{\sqrt{2}}\)赠的分母\(\frac{\sqrt{2}}{2}\)。 在不使用计算器的情况下\(\frac{1.414}{2}\)使用长除法进行近似值\(\frac{\sqrt{2}}{2}\)
    3. 你是否同意合理化分母可以简化计算? 为什么或者为什么不呢?

    自检

    ⓐ 完成练习后,使用这份清单来评估你对本节目标的掌握程度。

    此表有四列和四行。 这些列标有 “我可以...”、“自信地。”、“有帮助。” 和 “不,我不明白!” “我能...” 列下方的行是 “除以平方根”、“合理化一个单项分母。” 和 “合理化两个术语的分母”。 列下的所有其他行均为空。

    ⓑ 看完清单后,你认为你为下一节做好了充分的准备吗? 为什么或者为什么不呢?