1.
a. A= \(\left(\sqrt{12}+\sqrt{\left(-2\right)^2}-\sqrt{27}\right)\left(2+\sqrt{3}\right)\)
b. B= \(5\sqrt{3}+2-\sqrt{7-4\sqrt{3}}\)
c. C= \(2\sqrt{a}-\frac{5}{a}\sqrt{9a^3}+a\sqrt{\frac{4}{a}}-\frac{2}{a^2}\sqrt{25a^5}\)với a>0
d. D= \(\frac{1}{2\sqrt{a}-2}-\frac{1}{2\sqrt{a}+2}+\frac{\sqrt{a}}{1-a}\)
Rút gọn biểu thức
Giải nhanh giúp mk nha!Thanks <3
Chứng minh các đẳng thức sau
a) \(\left(\frac{2\sqrt{6}-\sqrt{3}}{2\sqrt{2}-1}+\frac{5+2\sqrt{5}}{2+\sqrt{5}}\right)\left(\sqrt{5}-\sqrt{3}\right)\)
b) \(\frac{a-b}{b^2}\sqrt{\frac{a^2b^4}{a^2-2ab+b^2}}=-a\)(Với b<a<0
c)\(\left(\sqrt{a}+\frac{1-a\sqrt{a}}{1-\sqrt{a}}\right)\left(\frac{1-\sqrt{a}}{1-a}\right)^2=1\)với a\(\ge0\),a khác 1
d) \(\left(\frac{3\sqrt{5}-\sqrt{15}}{\sqrt{27}-3}+\frac{2\sqrt{5}}{\sqrt{3}}\right)40\sqrt{15}=600\)
e) \(\left(1+\frac{x+\sqrt{x}}{\sqrt{x}+1}\right)\left(1-\frac{x-\sqrt{x}}{\sqrt{x}-1}\right)=1-x\)với x\(\ge0;x\ne1\)
bài 1: rút gọn
a, \(\sqrt{\frac{2}{3}}-\sqrt{24}+2\sqrt{\frac{3}{8}}+\sqrt{\frac{1}{6}}\)
b, \(\sqrt{\frac{2}{2-\sqrt{3}}}-\sqrt{\frac{2}{2+\sqrt{3}}}\)
c, \(2\sqrt{a}-\frac{5}{a}\sqrt{9a^3}+a\sqrt{\frac{4}{a}}-\frac{2}{a^2}\sqrt{25a^5}\left(vớia>0\right)\)
1 Rút gọn
A= ( \(\sqrt{48}-2\sqrt{3}+2\sqrt{5}\)5)\(\sqrt{5}-2\sqrt{45}:\sqrt{3}\)
B=(\(\frac{1}{\sqrt{5}-\sqrt{2}}-\frac{1}{\sqrt{5}+\sqrt{2}}+1\)).\(\frac{1}{\left(\sqrt{2}+1\right)^2}\)
C=\(2\sqrt{a}-\sqrt{9a^3}+a^2\sqrt{\frac{4}{a}}+\frac{2}{a}\sqrt{25a^5}\)với a>0
Giúp mình nhé, mình đang càn gấp :<<<
a) \(\left(1+\frac{a-\sqrt{a}}{\sqrt{a}-1}\right)\left(1-\frac{a+\sqrt{a}}{1+\sqrt{a}}\right)\)
b) \(\left(2-\frac{a-3\sqrt{a}}{\sqrt{a}-3}\right)\left(2-\frac{5\sqrt{a}-\sqrt{ab}}{\sqrt{b}-5}\right)\)
c) \(\left(3+\frac{a-2\sqrt{a}}{\sqrt{a}-2}\right)\left(3-\frac{3a+\sqrt{a}}{3\sqrt{a}+1}\right)\)
d) \(\left(\frac{a-\sqrt{a}}{\sqrt{a}-1}+2\right)\left(2-\frac{\sqrt{a}+a}{1+\sqrt{a}}\right)\)
Tính
a, \(\sqrt{75}-\sqrt{5\frac{1}{3}}+\frac{9}{2}\sqrt{2\frac{2}{3}}+2\sqrt{27}\)
b, \(\sqrt{48}+\sqrt{5\frac{1}{3}}+2\sqrt{75}-5\sqrt{1\frac{1}{3}}\)
c, \(\left(\sqrt{15}+2\sqrt{3}\right)^2+12\sqrt{5}\)
d, \(\left(\sqrt{6}+2\right)\left(\sqrt{3}-\sqrt{2}\right)\)
e, \(\left(\sqrt{3}+1\right)^2-2\sqrt{3}+4\)
f, \(\frac{1}{7+4\sqrt{3}}+\frac{1}{7-4\sqrt{3}}\)
Chứng minh
a, \(2\sqrt{2}\left(\sqrt{3}-2\right)+\left(1+2\sqrt{2}\right)^2-2\sqrt{6}=9\)
b, \(\sqrt{\sqrt{2}+1}-\sqrt{\sqrt{2}-1}=\sqrt{2\left(\sqrt{2}-1\right)}\)
Tìm GTNN
a, \(A=x-\sqrt{x}\)
b, \(B=\sqrt{x^2-2x+4}+1\)
Câu 1:Rút gọn biểu thức
a.A = \(\frac{3-\sqrt{3}}{\sqrt{3}}\) b.B = \(\frac{\sqrt{6+2\sqrt{5}}}{\sqrt{5}+1}\)c. C = \(\frac{2\sqrt{2}+\sqrt{6}}{4+\sqrt{12}}\) d. D = \(\frac{\sqrt{5+2\sqrt{6}}}{\sqrt{2}+\sqrt{3}}\)
e.E =\(\frac{1-\sqrt{a^3}}{a-1}\) f. F = \(\frac{\sqrt{7-4\sqrt{3}}}{\sqrt{3}-2}\) g. G = \(3.\sqrt{\frac{12\left(a-2\right)^2}{27}}\) h. H = \(\left(a-b\right).\sqrt{\frac{ab}{\left(a-b\right)^2}}\)
Bài 1: Rút gọn biểu thức:
\(A=\frac{a^3-3a+\left(a^2-1\right)\sqrt{a^2-4}-2}{a^3-3a+\left(a^2-1\right)\sqrt{a^2-4}+2}\left(a>2\right)\)
\(B=\sqrt{\frac{1}{a^2+b^2}+\frac{1}{\left(a+b\right)^2}+\sqrt{\frac{1}{a^4}+\frac{1}{b^4}+\frac{1}{\left(a^2+b^2\right)^2}}}\left(ab\ne0\right)\)
Bài 2: Tính giá trị của biểu thức:
\(E=\frac{1}{1\sqrt{2}+2\sqrt{1}}+\frac{1}{2\sqrt{3}+3\sqrt{2}}+\frac{1}{3\sqrt{4}+4\sqrt{3}}+...+\frac{1}{2017\sqrt{2018}+2018\sqrt{2017}}\)
Bài 3: Chứng minh rằng các biểu thức sau có gúa trị là số nguyên
\(A=\left(\sqrt{57}+3\sqrt{6}+\sqrt{38}+6\right)\left(\sqrt{57}-3\sqrt{6}-\sqrt{38}+6\right)\)
\(B=\frac{2\sqrt{3+\sqrt{5-\sqrt{13+\sqrt{48}}}}}{\sqrt{6}+\sqrt{2}}\)
\(\left(\frac{\sqrt{x}}{1-\sqrt{x}}+\frac{\sqrt{x}}{1+\sqrt{x}}\right)+\frac{3-\sqrt{x}}{x-1}\)
\(\left(\frac{3+\sqrt{x}}{3-\sqrt{x}}-\frac{3-\sqrt{x}}{3+\sqrt{x}}-\frac{4x}{x-9}\right):\left(\frac{5}{3-\sqrt{x}}-\frac{4\sqrt{x+2}}{3\sqrt{x}-x}\right)\)
\(\left(1+\frac{\sqrt{a}}{a+1}\right):\left(\frac{1}{\sqrt{a}-1}-\frac{2\sqrt{a}}{a\sqrt{a}+\sqrt{a}-a-1}\right)\)
\(\frac{3a-3+\sqrt{9a}}{a+\sqrt{a}-2}-\frac{\sqrt{a}+1}{\sqrt{a}+2}+\frac{\sqrt{a-2}}{1-\sqrt{a}}\)
