2.trục căn thức ở mẫu sau:
a\(\frac{2xy}{2\sqrt{x}+3\sqrt{y}}\)
b\(\frac{\sqrt{x}+\sqrt{y}}{2\sqrt{x}}\)
c\(\frac{2}{\sqrt{3}+1}\)
d\(\frac{6}{2\sqrt{3}+\sqrt{2}}\)
Trục căn thức ở mẫu:
a,\(\frac{1}{\sqrt{2}-1}\)
b,\(\frac{2}{\sqrt{3}+1}\)
c,\(\frac{5}{\sqrt{7}-\sqrt{2}}\)
d,\(\frac{6}{2\sqrt{3}+\sqrt{2}}\)
e,\(\frac{1}{2\sqrt{a}+1}\)
g,\(\frac{2xy}{2\sqrt{x}+3\sqrt{y}}\)
h,\(\frac{x\sqrt{x}-1}{\sqrt{x}-1}\)
i,\(\frac{a-9b}{\sqrt{a}-3\sqrt{b}}\)
k,\(\frac{15-2\sqrt{5}}{3\sqrt{15}-2\sqrt{3}}\)
trục căn thức ở mẫu :
a,\(\frac{3}{\sqrt{5}};\frac{2\sqrt{3}}{\sqrt{2}};\frac{a}{\sqrt{b}};\frac{x+1}{\sqrt{x^2-1}}\)
b,\(\frac{1}{\sqrt{3}+\sqrt{2}};\frac{2}{2-\sqrt{3}};\frac{\sqrt{2}+1}{\sqrt{2}-1};\frac{3\sqrt{2}}{\sqrt{3}+1}\)
c,\(\frac{1}{1+\sqrt{2}+\sqrt{3}}\)
d,\(\frac{1}{\sqrt{2\sqrt{3}-\sqrt{2}}.\sqrt{2}.\sqrt{\sqrt{2}+\sqrt{3}}}\)
a) \(\frac{3}{\sqrt{5}}=\frac{3\sqrt{5}}{\sqrt{5}.\sqrt{5}}=\frac{3\sqrt{5}}{5}\)
\(\frac{2\sqrt{3}}{\sqrt{2}}=\frac{2\sqrt{3}.\sqrt{2}}{\sqrt{2}.\sqrt{2}}=\frac{2\sqrt{6}}{2}=\sqrt{6}\)
\(\frac{a}{\sqrt{b}}=\frac{a\sqrt{b}}{\sqrt{b}.\sqrt{b}}=\frac{a\sqrt{b}}{b}\)
\(\frac{x+1}{\sqrt{x^2-1}}=\frac{\left(x+1\right)\left(\sqrt{x^2-1}\right)}{\left(\sqrt{x^2-1}\right)\left(\sqrt{x^2-1}\right)}\) = \(\frac{\left(\sqrt{x^2-1}\right)\left(x+1\right)}{x^2-1}\)
câu c chắc là như này
\(\frac{1}{1+\sqrt{2}+\sqrt{3}}=1+\frac{1}{\sqrt{2}+\sqrt{3}}\) = \(1+\frac{\sqrt{2}-\sqrt{3}}{\left(\sqrt{2}+\sqrt{3}\right)\left(\sqrt{2}-\sqrt{3}\right)}\)
= \(1+\frac{\sqrt{2}-\sqrt{3}}{2-3}=1+\frac{\sqrt{2}-\sqrt{3}}{-1}\) = \(1-\sqrt{2}+\sqrt{3}\)
Trục căn thức ở mẫu
a)\(\frac{\sqrt{3}-\sqrt{2}}{\sqrt{5}}\) b)\(\frac{2\sqrt{5}}{\sqrt{3}}\) c)\(\frac{1}{2\sqrt{32}}\) d)\(\frac{x+\sqrt{y}}{x\sqrt{y}}\) e)\(\frac{3\sqrt{2}-1}{3-\sqrt{8}}\) f)\(\frac{3-3\sqrt{2}}{2\sqrt{2}-3\sqrt{6}}\) g \(\frac{xy}{\sqrt{x}-\sqrt{y}}\)
Trục căn thức ở mẫu:
a) \(\frac{1}{\sqrt{2}+\sqrt{3}-\sqrt{6}}\)
b)\(\frac{1}{\sqrt{x}+\sqrt{y}+\sqrt{z}}\)
\(a,\frac{1}{\sqrt{2}+\sqrt{3}-\sqrt{6}}=\frac{\sqrt{2}+\sqrt{3}+\sqrt{6}}{\left(\sqrt{2}+\sqrt{3}-\sqrt{6}\right)\left(\sqrt{2}+\sqrt{3}+\sqrt{6}\right)}=\frac{\sqrt{2}+\sqrt{3}+\sqrt{6}}{\left(\sqrt{2}+\sqrt{3}\right)^2-\sqrt{6}^2}\)
\(=\frac{\sqrt{2}+\sqrt{3}+\sqrt{6}}{2\sqrt{6}-1}=\frac{\left(\sqrt{2}+\sqrt{3}+\sqrt{6}\right)\left(2\sqrt{6}+1\right)}{2\sqrt{6}^2-1^2}=\frac{4\sqrt{3}+6\sqrt{2}+12+\sqrt{2}+\sqrt{3}+\sqrt{6}}{11}\)\(=\frac{\sqrt{6}+5\sqrt{3}+7\sqrt{2}+12}{11}\)
\(b,\frac{1}{\sqrt{x}+\sqrt{y}+\sqrt{z}}=\frac{\sqrt{x}+\sqrt{y}-\sqrt{z}}{\left(\sqrt{z}+\sqrt{y}+\sqrt{z}\right)\left(\sqrt{x}+\sqrt{y}-\sqrt{z}\right)}=\frac{\sqrt{x}+\sqrt{y}-\sqrt{z}}{\left(\sqrt{x}+\sqrt{y}\right)^2-\sqrt{z}^2}\)
\(=\frac{\sqrt{x}+\sqrt{y}-\sqrt{z}}{x+2\sqrt{xy}+y-z}\)
Trục căn thức ở mẫu
a) A= \(\frac{1}{\sqrt{2}+\sqrt{3}-\sqrt{6}}\)
b) B = \(\frac{1}{\sqrt{x}+\sqrt{y}+\sqrt{z}}\)
c) C = \(\frac{12}{\sqrt{7}+2\sqrt{6}}\)
Trục căn ở mẫu:
\(a)\frac{5}{\sqrt{10}}\\ b)\frac{-2}{1-\sqrt{5}}\\ c)\frac{4}{\sqrt{3}+\sqrt{2}}\\ d)\frac{1}{3-2\sqrt{2}}\\ e)\frac{6-\sqrt{6}}{1-\sqrt{6}}\\ g)\frac{3\sqrt{2}-2\sqrt{3}}{2\left(\sqrt{3}-\sqrt{2}\right)}\\ h)\frac{\sqrt{3}-3}{\sqrt{3}-1}\\ i)\frac{\sqrt{15}}{5\sqrt{3}+3\sqrt{5}}\)
Trục căn thức ở mẫu:
A) \(\frac{1}{\sqrt{X-1}}\)
B) \(\frac{X+2}{\sqrt{X^2-4}}\)
C) \(\frac{A}{\sqrt{X^N}}\:\)( N lẻ)
D) \(\frac{2-\sqrt{3}}{\sqrt{2-\sqrt{3}}}\)
E) \(\frac{2}{\sqrt{7-2\sqrt{6}}}\)
1.Khử mẫu biểu thức lấy căn
a) \(\frac{a}{b}\sqrt{\frac{b}{a}}\)
b) \(\sqrt{\frac{1}{b}+\frac{1}{b^2}}\)
c) \(3xy\sqrt{\frac{12}{xy}}\)
2.Trục căn thức ở mẫu
a) \(\frac{1}{2+\sqrt{3}}\)
b) \(\frac{\sqrt{2}+1}{\sqrt{2}-1}\)
c) \(\frac{3\sqrt{2}}{\sqrt{3}+1}\)
d) \(\frac{1}{1+\sqrt{2}+\sqrt{3}}\)
e) \(\frac{1}{\sqrt{2\sqrt{3}-\sqrt{2}}.\sqrt{\sqrt{2}}}\)
3.a) Tính
\(\frac{3+4\sqrt{3}}{\sqrt{6}+\sqrt{2}-\sqrt{5}}\)
b) Tính giá trị
\(M=\frac{\left(x-1\right)\sqrt{3}}{\sqrt{x^2-x+1}}\) với \(x=2+\sqrt{3}\)
Bài 11 Trục căn thức ở mẫu
a) \(\frac{\sqrt{2}-\sqrt{3}}{2\sqrt{3}}\)
b)\(\frac{x+a\sqrt{x}}{a\sqrt{x}}\)
c)\(\frac{x-y}{\sqrt{x}-\sqrt{y}}\)
d)\(\frac{x}{2\sqrt{x}-3\sqrt{y}}\)
a/ \(\frac{\sqrt{2}-\sqrt{3}}{2\sqrt{3}}=\frac{\sqrt{3}\left(\sqrt{2}-\sqrt{3}\right)}{2.3}=\frac{\sqrt{6}-\sqrt{9}}{6}=\frac{\sqrt{6}-3}{6}\)
b/ \(\frac{x+a\sqrt{x}}{a\sqrt{x}}=\frac{\sqrt{x}\left(x+a\sqrt{x}\right)}{a.\left|x\right|}=\frac{x\sqrt{x}+a\left|x\right|}{a\left|x\right|}\)
c/ \(\frac{x-y}{\sqrt{x}-\sqrt{y}}=\frac{\left(\sqrt{x}+\sqrt{y}\right)\left(\sqrt{x}+\sqrt{y}\right)\left(\sqrt{x}-\sqrt{y}\right)}{\left(\sqrt{x}-\sqrt{y}\right)\left(\sqrt{x}+\sqrt{y}\right)}=\frac{\left(\sqrt{x}+\sqrt{y}\right)^2\left(\sqrt{x}-\sqrt{y}\right)}{\left|x\right|-\left|y\right|}\)
d/ \(\frac{x}{2\sqrt{x}-3\sqrt{y}}=\frac{x\left(2\sqrt{x}+3\sqrt{y}\right)}{\left(2\sqrt{x}-3\sqrt{y}\right)\left(2\sqrt{x}+3\sqrt{y}\right)}=\frac{2x\sqrt{x}+3x\sqrt{y}}{4\left|x\right|-9\left|y\right|}\)