a: \(2\sqrt{5}-5\sqrt{2}< 0< 1\)
b: \(\sqrt{\dfrac{8}{3}}=\dfrac{2\sqrt{2}}{\sqrt{3}}=\dfrac{2\sqrt{6}}{3}< \dfrac{3}{4}\)
a: \(2\sqrt{5}-5\sqrt{2}< 0< 1\)
b: \(\sqrt{\dfrac{8}{3}}=\dfrac{2\sqrt{2}}{\sqrt{3}}=\dfrac{2\sqrt{6}}{3}< \dfrac{3}{4}\)
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: \(\left(\dfrac{a^3\sqrt[]{a}-2a^3\sqrt{b}+\sqrt[3]{a^2}-\sqrt[3]{b}}{\sqrt[3]{a^2-\sqrt[3]{ab}}}+\dfrac{\sqrt[3]{a^2b}-\sqrt[3]{ab^2}}{\sqrt[3]{a}-\sqrt[3]{b}}\right)1\dfrac{1}{\sqrt[3]{a^2}}\)
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= \(\sqrt[3]{2+\sqrt{5}}+\sqrt[3]{2-\sqrt{5}}\)
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
Bài 1: Tính
A= \(\sqrt[3]{2+\sqrt{5}}+\sqrt[3]{2-\sqrt{5}}\)
B=\(\sqrt[3]{9+4\sqrt{5}}+\sqrt[3]{9-4\sqrt{5}}\)
Bài 2: PTTNT:
a) \(\sqrt[3]{15}-\sqrt[3]{21}\)
b)\(\sqrt[3]{3}-3\)
c)\(\sqrt[3]{a^2x}+\sqrt[3]{b^2x}\)
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,\(\dfrac{\sqrt[3]{a^4}+\sqrt[3]{a^2b^2}+\sqrt[3]{b^4}}{\sqrt[3]{a^2}+\sqrt[3]{ab}+\sqrt[3]{b^2}}\)
So sánh:M=\(\sqrt[3]{7+5\sqrt{2}}\)+\(\sqrt[3]{7-5\sqrt{2}}\) và N=\(\dfrac{4}{\sqrt[3]{9}}\)
Trục căn thức ở mẫu
a) \(\dfrac{1}{1-\sqrt[3]{5}}\)
b) \(\dfrac{1}{\sqrt[3]{2}+\sqrt[3]{3}}\)
c) \(\dfrac{1}{1+\sqrt[3]{2}+\sqrt[3]{4}}\)
tính
a. \(\dfrac{\sqrt[3]{125}.\sqrt[3]{\dfrac{16}{10}}.\sqrt[3]{-0,5}}{\sqrt[3]{4}+\sqrt[3]{2}+1}\)
b.\(\sqrt[]{3+\sqrt[]{5}+\sqrt[]{10+6\sqrt[]{5}}}\)
Tính giá trị các biểu thức:
a)( \(\frac{1}{2}\sqrt[3]{9}-2\sqrt[3]{3}+3\sqrt[3]{\frac{1}{3}}\)) : \(2\sqrt[3]{\frac{1}{3}}\)
b)\(\left(12\sqrt[3]{2}+\sqrt[3]{16}-2\sqrt[3]{2}\right)\left(5\sqrt[3]{4}-3\sqrt[3]{\frac{1}{2}}\right)\)
Rút gọn biểu thức:
a, √45 - √20 - 1/4√80 + √125
b, √81a - √36a - 1/5√25a với a > 0
c, 3√27 - 3√- 8 - 3√-125 -> câu này là căn bậc 3 nhé