Toán Lớp 9: Rút gọn biểu thức
√ ($\frac{1}{ 3-√5}$+ $\frac{1}{3+√5}$ ) ÷ $\frac{5-√5}{√5-1}$
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Toán Lớp 9: Rút gọn biểu thức
√ ($\frac{1}{ 3-√5}$+ $\frac{1}{3+√5}$ ) ÷ $\frac{5-√5}{√5-1}$
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Bạn tham khảo
=sqrt{(3+sqrt{5})/((3-sqrt{5})(3+sqrt{5}))+(3-sqrt{5})/((3+sqrt{5})(3-sqrt{5}))}:(sqrt{5}.(sqrt{5}-1))/(sqrt{5}-1)
=sqrt{(3+sqrt{5})/(9-5)+(3-sqrt{5})/(9-5)}:sqrt{5}
=sqrt{(3+sqrt{5})/4+(3-sqrt{5})/4}. 1/sqrt{5}
=sqrt{(3+sqrt{5}+3-sqrt{5})/4}. 1/sqrt{5}
=sqrt{6/4}. 1/sqrt{5}
=sqrt{6}/sqrt{4} . 1/sqrt{5}
=sqrt{6}/sqrt{20}
=(sqrt{20}sqrt{6})/20
=(sqrt{4}.sqrt{5}.sqrt{6})/(2.10)
=sqrt{30}/10