a) \(\sqrt[4]{56-24\sqrt{5}}=\sqrt[4]{6^2-2.6.2\sqrt{5}+\left(2\sqrt{5}\right)^2}=\sqrt[4]{\left(6-2\sqrt{5}\right)^2}=6-2\sqrt{5}\)
a) \(\sqrt[3]{5-\sqrt{17}}+\sqrt[3]{5+\sqrt{17}}\)
b) \(\dfrac{1}{\sqrt[3]{4-\sqrt{15}}}+\sqrt[3]{4-\sqrt{15}}\)
c) \(\dfrac{\sqrt[3]{a^4}+\sqrt[3]{a^2b^2}+\sqrt[3]{b^4}}{\sqrt[3]{a^2}+\sqrt[3]{ab}+\sqrt[3]{b^2}}\)
Rút gọn các biểu thức sau
Rút gọn
\(\sqrt[3]{4-2\sqrt{6}}+\sqrt[3]{4+2\sqrt{6}}\)
1.Chứng minh:\(\dfrac{a+\sqrt{2+\sqrt{5}.}\sqrt{\sqrt{9-4\sqrt{5}}}}{3\sqrt{2-\sqrt{5}}.\sqrt[3]{\sqrt{9+4\sqrt{5}-}3\sqrt{a^2}+\sqrt[3]{a}}}\)=\(-\sqrt[3]{a}-1\)
2.Rút gọn: \(\left(\dfrac{a^3\sqrt[]{a}-2a^3\sqrt{b}+\sqrt[3]{a^2}-\sqrt[3]{b}}{\sqrt[3]{a^2-\sqrt[3]{ab}}}+\dfrac{\sqrt[3]{a^2b}-\sqrt[3]{ab^2}}{\sqrt[3]{a}-\sqrt[3]{b}}\right)1\dfrac{1}{\sqrt[3]{a^2}}\)
cmr\(\dfrac{\sqrt[4]{17+12\sqrt{2}}+\sqrt[4]{17-12\sqrt{2}}}{2}=\sqrt{2}\)
Rút gọn : A = \(\sqrt[3]{4+\sqrt{80}}-\sqrt[3]{\sqrt{80}-4}\)
Rút gọn các biểu thức:
a) A= \(\frac{\sqrt[3]{135}}{\sqrt[3]{5}}-\sqrt[3]{54}\sqrt[3]{4}\)
b) B= \(\left(\frac{1}{2}\sqrt[3]{2}-\frac{1}{4}\sqrt[3]{16}\right).\sqrt[3]{4}\)
c) C= \(\sqrt[3]{\left(\sqrt{2}+1\right)\left(3+2\sqrt{2}\right)}\)
d) D= \(\sqrt[3]{3+3\sqrt[3]{2}+3\sqrt[3]{4}}\)
e) E= \(\sqrt[3]{2+\sqrt{5}}+\sqrt[3]{2-\sqrt{5}}\)
1.Tìm x:\(\left(x-3\right)^3\)=\(\dfrac{1}{64}\)
2.Chứng minh:
a,(\(\sqrt[3]{\sqrt[]{9+4\sqrt[]{5}}}\).\(\sqrt[3]{\sqrt[]{5.2}}\)).\(\sqrt[3]{\sqrt[]{5-2}}\) -2,1 <0
3.Rút gọn,\(\dfrac{\sqrt[3]{a^4}+\sqrt[3]{a^2b^2}+\sqrt[3]{b^4}}{\sqrt[3]{a^2}+\sqrt[3]{ab}+\sqrt[3]{b^2}}\)
A =\(\dfrac{x\sqrt[]{x}-3}{x-2\sqrt[]{x}-3}-\dfrac{2\left(\sqrt[]{x}-3\right)}{\sqrt[]{x}+1}+\dfrac{\sqrt[]{x}+3}{3-\sqrt[]{x}}\)
a. rút gọn A
b. Tính A với x = \(14-6\sqrt[]{5}\)
c. tìm min A
A=\(\dfrac{x\sqrt{x}-3}{x-2\sqrt{x}-3}-\dfrac{2\left(\sqrt{x}-3\right)}{\sqrt{x}+1}+\dfrac{\sqrt{x}+3}{3-\sqrt{x}}\)
a) Rút gọn A
b) Tính A với x=14-6\(\sqrt{5}\)
c) Tìm Min A
