A=\(\sqrt[3]{20+14\sqrt{2}}+\sqrt[3]{20-14\sqrt{2}}\)
=\(\sqrt[3]{\left(2+\sqrt{2}\right)^3}+\sqrt[3]{\left(2-\sqrt{2}\right)^3}\)
=\(2+\sqrt{2}+2-\sqrt{2}=4=2\sqrt{2}\)
ta thấy : 2\(\sqrt{5}>2\sqrt{2}\)
=> B>A
1.Tính các giá trị biểu thức:
a.\(x=\sqrt[3]{5+2\sqrt{3}}+\sqrt[3]{5-2\sqrt{3}}\)
b.\(x=\sqrt[3]{\sqrt{5}+2}-\sqrt[3]{\sqrt{5}-2}\)
c.\(x=\sqrt[3]{182+\sqrt{33125}}+\sqrt[3]{182-\sqrt{33125}}\)
d.\(x=\sqrt[3]{20+14\sqrt{2}}+\sqrt[3]{20-14\sqrt{2}}\)
Tính: \(\sqrt[3]{20+14\sqrt{2}}+\sqrt[3]{20-14\sqrt{2}}\)
Tính:
\(\sqrt[3]{20+14\sqrt{2}}+\sqrt[3]{20-14\sqrt{2}}\)
Tính:
a) \(\sqrt[3]{\left(\sqrt{2}+1\right)\left(3+2\sqrt{2}\right)}\)
b) \(\sqrt[3]{\left(4-2\sqrt{3}\right)\left(\sqrt{3}-1\right)}\)
c) \(\left(\sqrt[3]{4}+1\right)^3-\left(\sqrt[3]{4}-1\right)^3\)
d) \(\left(\sqrt[3]{9}-\sqrt[3]{6}+\sqrt[3]{4}\right)\left(\sqrt[3]{3}+\sqrt[3]{2}\right)\)
e) \(\sqrt[3]{20+14\sqrt{2}}+\sqrt[3]{20-14\sqrt{2}}\)
Mọi người giúp em với ạ!!!!!!!!!!!
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
so sánh
\(;\sqrt{2}+1vs\sqrt[3]{7+5\sqrt{2};}\) \(-6\sqrt[3]{7}\&7\sqrt[3]{\left(-6\right)}\)\(;\sqrt[3]{4}+\sqrt[3]{7}\&\sqrt[3]{11}\)\(;\sqrt[3]{10}-2vs\sqrt[3]{2}\)
Cho \(x=\dfrac{\left(\sqrt{5}+2\right)\sqrt[3]{17\sqrt{5}-38}}{\sqrt{5}+\sqrt{14-6\sqrt{5}}}\)
Tính \(A=\left(3x^3+8x^2+2\right)^{1998}\)
So sánh các cặp số sau:
a)6 và \(2\sqrt[3]{26}\)
b)\(2\sqrt[3]{6}\) và \(\sqrt[3]{47}\)
