Ôn tập chương 1: Căn bậc hai. Căn bậc ba
Các câu hỏi tương tự
Thực hiện phép tính:
1)Aleft(dfrac{1}{3-sqrt{5}}-dfrac{1}{3+sqrt{5}}right) . dfrac{5-sqrt{5}}{sqrt{5}-1}
2)B dfrac{1}{1
+sqrt{2}} +dfrac{1}{sqrt{2}+sqrt{3}}+.....+dfrac{1}{sqrt{99}+sqrt{100}}
3)C sqrt[3]{7+5sqrt{2}} - sqrt[3]{7-5sqrt{2}}
4) D sqrt[3]{9+4sqrt{5}}+sqrt[3]{9-4sqrt{3}}
Đọc tiếp
Thực hiện phép tính:
1)A=\(\left(\dfrac{1}{3-\sqrt{5}}-\dfrac{1}{3+\sqrt{5}}\right)\) . \(\dfrac{5-\sqrt{5}}{\sqrt{5}-1}\)
2)B = \(\dfrac{1}{1 +\sqrt{2}}\) +\(\dfrac{1}{\sqrt{2}+\sqrt{3}}\)+.....+\(\dfrac{1}{\sqrt{99}+\sqrt{100}}\)
3)C = \(\sqrt[3]{7+5\sqrt{2}}\) - \(\sqrt[3]{7-5\sqrt{2}}\)
4) D = \(\sqrt[3]{9+4\sqrt{5}}\)+\(\sqrt[3]{9-4\sqrt{3}}\)
CMR: \(\sqrt[3]{\sqrt[3]{2}-1}=\sqrt[3]{\dfrac{1}{9}}-\sqrt[3]{\dfrac{2}{9}}+\sqrt[3]{\dfrac{4}{9}}\)
1.\(\dfrac{15\sqrt{x}-11}{x+2\sqrt{x}-3}+\dfrac{3\sqrt{x}-2}{1-\sqrt{x}}-\dfrac{2\sqrt{x}+3}{\sqrt{x}+3}\)
2.\(\dfrac{x\sqrt{x}+1}{x-1}-\dfrac{x-1}{\sqrt{x}+1}\)
3.\(\left(1-\dfrac{4}{\sqrt{x}+1}+\dfrac{1}{x-1}\right):\dfrac{x-2\sqrt{x}}{x-1}\)
4.\(\dfrac{\sqrt{x}}{\sqrt{x}+3}+\dfrac{2\sqrt{x}}{\sqrt{x}-3}-\dfrac{3x+9}{x-9}\)
Rút gọn
Adfrac{1}{sqrt{1}-sqrt{2}}-dfrac{1}{sqrt{2}-sqrt{3}}+dfrac{1}{sqrt{3}-sqrt{4}}-...-dfrac{1}{sqrt{24}-sqrt{25}}
Bdfrac{5}{4+sqrt{11}}+dfrac{11-3sqrt{11}}{sqrt{11}-3}-dfrac{4}{sqrt{5}-1}+sqrt{left(sqrt{5}-2right)^2}
Cdfrac{sqrt{x}+1}{xsqrt[]{x}+x+sqrt{x}}:dfrac{1}{x^2-sqrt{x}} (với x0; x#1)
Ddfrac{sqrt{x^2-10x+25}}{x-5}
Đọc tiếp
Rút gọn
A=\(\dfrac{1}{\sqrt{1}-\sqrt{2}}-\dfrac{1}{\sqrt{2}-\sqrt{3}}+\dfrac{1}{\sqrt{3}-\sqrt{4}}-...-\dfrac{1}{\sqrt{24}-\sqrt{25}}\)
B=\(\dfrac{5}{4+\sqrt{11}}+\dfrac{11-3\sqrt{11}}{\sqrt{11}-3}-\dfrac{4}{\sqrt{5}-1}+\sqrt{\left(\sqrt{5}-2\right)^2}\)
C=\(\dfrac{\sqrt{x}+1}{x\sqrt[]{x}+x+\sqrt{x}}:\dfrac{1}{x^2-\sqrt{x}}\) (với x>0; x#1)
D=\(\dfrac{\sqrt{x^2-10x+25}}{x-5}\)
Bài 1: Cho A dfrac{1}{2sqrt{1}+1sqrt{2}}+dfrac{1}{3sqrt{2}+2sqrt{3}}+dfrac{1}{4sqrt{3}+3sqrt{4}}+...+dfrac{1}{100sqrt{99}+99sqrt{100}}
So sánh A với 1
Bài 2: Tính
A left(dfrac{3}{sqrt{2}+1}+dfrac{14}{2sqrt{2}-1}-dfrac{4}{2-sqrt{2}}right).left(sqrt{8}+2right)
Bài 3: Tính tổng
Sdfrac{1}{sqrt{2}+sqrt{3}}+dfrac{1}{sqrt{3}+sqrt{4}}+dfrac{1}{sqrt{4}+sqrt{5}}+...+dfrac{1}{sqrt{2018}+sqrt{2019}}
Đọc tiếp
Bài 1: Cho A = \(\dfrac{1}{2\sqrt{1}+1\sqrt{2}}+\dfrac{1}{3\sqrt{2}+2\sqrt{3}}+\dfrac{1}{4\sqrt{3}+3\sqrt{4}}+...+\dfrac{1}{100\sqrt{99}+99\sqrt{100}}\)
So sánh A với 1
Bài 2: Tính
A = \(\left(\dfrac{3}{\sqrt{2}+1}+\dfrac{14}{2\sqrt{2}-1}-\dfrac{4}{2-\sqrt{2}}\right).\left(\sqrt{8}+2\right)\)
Bài 3: Tính tổng
S=\(\dfrac{1}{\sqrt{2}+\sqrt{3}}+\dfrac{1}{\sqrt{3}+\sqrt{4}}+\dfrac{1}{\sqrt{4}+\sqrt{5}}+...+\dfrac{1}{\sqrt{2018}+\sqrt{2019}}\)
Giải PT:a) dfrac{1}{2}sqrt{x-1}-dfrac{3}{2}sqrt{9x-9}+24sqrt{dfrac{x-1}{64}}-17b) sqrt{18x-9}-0,5sqrt{2x-1}+dfrac{1}{2}sqrt{25left(2x-1right)}+sqrt{49left(2x-1right)}24c) sqrt{36x-72}-15sqrt{dfrac{x-2}{25}}4left(5+sqrt{x-2}right)d) sqrt{dfrac{1}{3x+2}}-dfrac{1}{2}sqrt{dfrac{9}{3x+2}}+sqrt{dfrac{16}{3x+2}}-5sqrt{dfrac{1}{12x+8}}1e) dfrac{1}{2}sqrt{dfrac{49x}{x+2}}-3sqrt{dfrac{x}{4x+8}}-sqrt{dfrac{x}{x+2}}-sqrt{5}0
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Giải PT:
a) \(\dfrac{1}{2}\sqrt{x-1}-\dfrac{3}{2}\sqrt{9x-9}+24\sqrt{\dfrac{x-1}{64}}=-17\)
b) \(\sqrt{18x-9}-0,5\sqrt{2x-1}+\dfrac{1}{2}\sqrt{25\left(2x-1\right)}+\sqrt{49\left(2x-1\right)}=24\)
c) \(\sqrt{36x-72}-15\sqrt{\dfrac{x-2}{25}}=4\left(5+\sqrt{x-2}\right)\)
d) \(\sqrt{\dfrac{1}{3x+2}}-\dfrac{1}{2}\sqrt{\dfrac{9}{3x+2}}+\sqrt{\dfrac{16}{3x+2}}-5\sqrt{\dfrac{1}{12x+8}}=1\)
e) \(\dfrac{1}{2}\sqrt{\dfrac{49x}{x+2}}-3\sqrt{\dfrac{x}{4x+8}}-\sqrt{\dfrac{x}{x+2}}-\sqrt{5}=0\)
chứng minh đẳng thúc
\(\dfrac{5}{4-\sqrt{11}}+\dfrac{1}{3+\sqrt{7}}-\dfrac{6}{\sqrt{7}-2}-\dfrac{\sqrt{7}-5}{2}=4+\sqrt{11}-3\sqrt{7}\)
a)\(\dfrac{5}{4-\sqrt{11}}+\dfrac{1}{3+\sqrt{7}}-\dfrac{6}{\sqrt{7-2}}-\dfrac{\sqrt{7-5}}{2}\) =4+\(\sqrt{11-3\sqrt{7}}\)
b)\(\dfrac{\sqrt{x+\sqrt{y}}}{2\left(\sqrt{x}-\sqrt{y}\right)}-\dfrac{\sqrt{x-\sqrt{y}}}{2\left(\sqrt{x+\sqrt{y}}\right)}-\dfrac{y+x}{y-x}=\dfrac{\sqrt{x}+\sqrt{y}}{\sqrt{x-\sqrt{y}}}\)
RÚt gọn c)dfrac{1}{sqrt{1}+sqrt{2}}+dfrac{1}{sqrt{2}+sqrt{3}}+dfrac{1}{sqrt{3}+sqrt{4}}+...+dfrac{1}{sqrt{899}+sqrt{900}}
d)dfrac{4}{sqrt{7}-sqrt{3}}+dfrac{6}{3+sqrt{3}}+dfrac{sqrt{7}-7}{sqrt{7}-1}
e) dfrac{x+5-xsqrt{x-1}}{x-1-3sqrt{x-1}}
b) dfrac{sqrt{5}-sqrt{15}}{1-sqrt{3}}-sqrt{21+4sqrt{5}}
)) giúp câu nào được thì giúp ạ 3
Đọc tiếp
RÚt gọn c)\(\dfrac{1}{\sqrt{1}+\sqrt{2}}+\dfrac{1}{\sqrt{2}+\sqrt{3}}+\dfrac{1}{\sqrt{3}+\sqrt{4}}+...+\dfrac{1}{\sqrt{899}+\sqrt{900}}\)
d)\(\dfrac{4}{\sqrt{7}-\sqrt{3}}+\dfrac{6}{3+\sqrt{3}}+\dfrac{\sqrt{7}-7}{\sqrt{7}-1}\)
e) \(\dfrac{x+5-x\sqrt{x-1}}{x-1-3\sqrt{x-1}}\)
b) \(\dfrac{\sqrt{5}-\sqrt{15}}{1-\sqrt{3}}-\sqrt{21+4\sqrt{5}}\)
=)) giúp câu nào được thì giúp ạ <3