so sanh
\(2\sqrt{5}-5\)va \(\sqrt{5}-3\)
\(\sqrt{17}+\sqrt{26}\) va 9
so sanh
a) 2^90 va 5^36
b) 99^200 va 9999^100
c) 2^150 va 3^100
d) \(\sqrt{26+2}\) va \(\sqrt{26}\)+ \(\sqrt{2}\)
bai 4 so sanh cac so thuc
\(\frac{4}{9}va\)0,4(5)
\(\sqrt[2]{3}va\sqrt[3]{2}\)
So sanh:
a, \(\sqrt{\dfrac{35}{34}}\) va \(\sqrt{\dfrac{71}{70}}\)
b, \(4\sqrt{5}-3\sqrt{2}\) va 5
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SO SANH
\(-2\sqrt{5}va-5\sqrt{2}\)
\(-2\sqrt{5}=-\sqrt{2^2.5}=-\sqrt{20}\)
\(-5\sqrt{2}=-\sqrt{5^2.2}=-\sqrt{50}\)
\(\Rightarrow-\sqrt{20}>-\sqrt{50}\)
hay \(-2\sqrt{5}>-5\sqrt{2}\)
\(-2\sqrt{5}=-\sqrt{2^2.5}=-\sqrt{20}\)
\(-5\sqrt{2}=-\sqrt{5^2.2}=-\sqrt{50}\)
vì \(20< 50\)nen \(-\sqrt{20}>-\sqrt{50}\)
so sanh x va y biet
a) x=\(2\sqrt{7}\)va y=\(3\sqrt{3}\)
b) x=\(6\sqrt{2}\)va y=\(5\sqrt{3}\)
c) x=\(\sqrt{31}-\sqrt{33}\) va y=\(6-\sqrt{11}\)
So sánh:
1,\(2-\sqrt{2}va\frac{1}{2}\)
2, \(2\sqrt{3}-5va\sqrt{3}-4\)
3, \(\sqrt{3}-3\sqrt{2}va-4\sqrt{3}+5\sqrt{2}\)
4,\(1-\sqrt{3}va\sqrt{2}-\sqrt{6}\)
5, \(\sqrt{4\sqrt{5}}va\sqrt{5\sqrt{3}}\)
6, \(\sqrt{\sqrt{6}-\sqrt{5}}-\sqrt{\sqrt{3}-\sqrt{2}}va..0\)
7, \(-2\sqrt{\frac{1}{2}\sqrt{5}}va-3\sqrt{\frac{1}{3}\sqrt{2}}\)
a) So sanh: \(\sqrt{17}+\sqrt{26}+1\)va \(\sqrt{99}\)
b) CMR: \(\frac{1}{\sqrt{1}}+\frac{1}{\sqrt{2}}+\frac{1}{\sqrt{3}}+...+\frac{1}{\sqrt{100}}>10\)
a)\(\sqrt{17}+\sqrt{26}+1>\sqrt{16}+\sqrt{25}+1=4+5+1=10\)
b) \(\frac{1}{\sqrt{1}}+\frac{1}{\sqrt{2}}+\frac{1}{\sqrt{3}}+.....+\frac{1}{\sqrt{100}}>\frac{1}{\sqrt{100}}+\frac{1}{\sqrt{100}}+\frac{1}{\sqrt{100}}+.......+\frac{1}{\sqrt{100}}=\frac{100}{\sqrt{100}}=10\)
so sanh ko dung may tinh
1 )\(\sqrt{3}\) +\(\sqrt{7}\) va 2+ \(\sqrt{6}\)
2) \(\sqrt{7}\) - \(\sqrt{5}\) va \(\sqrt{6}-2\)
3) \(\sqrt{11}-\sqrt{7}vs\sqrt{7}-\sqrt{3}\)
1: \(\left(\sqrt{3}+\sqrt{7}\right)^2=10+2\sqrt{21}\)
\(\left(2+\sqrt{6}\right)^2=10+4\sqrt{6}\)
mà 2 căn 21<4 căn 6
nên căn 3+căn 7<2+căn 6
2: \(\sqrt{7}-\sqrt{5}=\dfrac{2}{\sqrt{7}+\sqrt{5}}\)
\(\sqrt{6}-2=\dfrac{2}{\sqrt{6}+2}\)
mà \(\sqrt{7}+\sqrt{5}>\sqrt{6}+2\)
nên \(\sqrt{7}-\sqrt{5}< \sqrt{6}-2\)
3: \(\sqrt{11}-\sqrt{7}=\dfrac{4}{\sqrt{11}+\sqrt{7}}\)
\(\sqrt{7}-\sqrt{3}=\dfrac{4}{\sqrt{7}+\sqrt{3}}\)
mà căn 11>căn 3
nên \(\sqrt{11}-\sqrt{7}< \sqrt{7}-\sqrt{3}\)
\(0,5\sqrt{100}-\sqrt[]{\frac{4}{25}}va\left(\sqrt{\frac{10}{9}}-\sqrt{\frac{9}{16}}\right):5\)
so sanh
(1+1_1/4+1_1/2+1_3/4+2+2_1/4+2_1/2+2_3/4+......+4_3/4) : 23 tính nhanh !!!!! Ai nhanh mình kêu anh chị mình vào nha !! Mình cần gấp lắm !! Cảm ơn mọi người