Phân tích số dưới dấu căn ra thừa số nguyên tố hoặc đổi thành phân số.
3\(\sqrt{ }\)512 = 3\(\sqrt{ }\)29 = 3\(\sqrt{ }\)(23)3= 23 = 8
3\(\sqrt{ }\)-729 = – 3\(\sqrt{ }\)729 = – 3\(\sqrt{ }\)36=- 3\(\sqrt{ }\)(32)3 = – (32)= -9
3\(\sqrt{ }\)-216 = -3/5
3\(\sqrt{ }\)-0,008 = -1/5
Tính:
a)\(\sqrt[3]{125}.\sqrt[3]{\dfrac{16}{10}}.\sqrt[3]{-0,5}\)
b) \(\dfrac{\sqrt[3]{4}+\sqrt[3]{2}+2}{\sqrt[3]{4}+\sqrt[3]{2}+1}\)
c) \(\sqrt{3}+\sqrt[3]{10+6\sqrt{3}}\)
d) \(\dfrac{4+2\sqrt{3}}{\sqrt[3]{10+6\sqrt{3}}}\)
e) E=\(\sqrt[3]{2+10\sqrt{\dfrac{1}{27}}}+\sqrt[3]{2-10\sqrt{\dfrac{1}{27}}}\)
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
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: \(\left(\dfrac{a^3\sqrt[]{a}-2a^3\sqrt{b}+\sqrt[3]{a^2}-\sqrt[3]{b}}{\sqrt[3]{a^2-\sqrt[3]{ab}}}+\dfrac{\sqrt[3]{a^2b}-\sqrt[3]{ab^2}}{\sqrt[3]{a}-\sqrt[3]{b}}\right)1\dfrac{1}{\sqrt[3]{a^2}}\)
so sánh
\(;\sqrt{2}+1vs\sqrt[3]{7+5\sqrt{2};}\) \(-6\sqrt[3]{7}\&7\sqrt[3]{\left(-6\right)}\)\(;\sqrt[3]{4}+\sqrt[3]{7}\&\sqrt[3]{11}\)\(;\sqrt[3]{10}-2vs\sqrt[3]{2}\)
Thực hiện phép tính
a)\(\dfrac{\sqrt[3]{135}}{\sqrt[3]{5}}-\sqrt[3]{54}.\sqrt[3]{4}\)
b)\(\left(\sqrt[3]{25}-\sqrt[3]{10}+\sqrt[3]{4}\right)\)\(\left(\sqrt[3]{5}+\sqrt[3]{2}\right)\)
tính
a. \(\dfrac{\sqrt[3]{125}.\sqrt[3]{\dfrac{16}{10}}.\sqrt[3]{-0,5}}{\sqrt[3]{4}+\sqrt[3]{2}+1}\)
b.\(\sqrt[]{3+\sqrt[]{5}+\sqrt[]{10+6\sqrt[]{5}}}\)
Tìm số lớn hơn:
a)\(3\sqrt[3]{2}\) và \(\sqrt[3]{53}\)
b)22 và \(3\sqrt[3]{394}\)
Tính
a.A=\(\sqrt[3]{2+\sqrt{5}}+\sqrt[3]{2-\sqrt{5}}\)
b.B=\(\sqrt[3]{3+\sqrt{9+\dfrac{125}{7}}}-\sqrt[3]{-3+\sqrt{9+\dfrac{125}{7}}}\)
c.C=\(\sqrt[3]{26+15\sqrt{3}}.\left(2-\sqrt{3}\right)+\sqrt[3]{9+\sqrt{80}}+\sqrt[3]{9-\sqrt{80}}\)
