\(\sqrt{27}\)-\(\sqrt{12}\)-\(\sqrt{2016}\)và -44
không dùng máy tính gãy so sánh \(\sqrt{27}-\sqrt{12}-\sqrt{2016}\) và -44
Không dùng máy tính, hãy so sánh:
\(\sqrt{27}-\sqrt{12}-\sqrt{2016}\)và -44
ko dùng máy tính hãy so sánh :
\(\sqrt{27}-\sqrt{12}-\sqrt{2016}và-44\)
\(\sqrt{27}-\sqrt{12}-\sqrt{2016}>\sqrt{25}-\sqrt{16}-\sqrt{2025}\)
\(=5-4-45=-44\)
Vậy \(\sqrt{27}-\sqrt{12}-\sqrt{2016}>-44\)
Có : \(\sqrt{12}< \sqrt{16}=4\)
\(\sqrt{2016}< \sqrt{2025}\) => \(\sqrt{12}+\sqrt{2016}< 4+45\)
=> \(-\sqrt{12}-\sqrt{2016}>-49\)(1)
Lại có : \(\sqrt{27}>\sqrt{25}=5\)(2)
Từ (1),(2) có : \(\sqrt{27}-\sqrt{12}-\sqrt{2016}>5-49\)or \(\sqrt{27}-\sqrt{12}-\sqrt{2016}>-44\)
Chứng minh rằng:\(\frac{43}{44}\le\frac{1}{2+\sqrt{2}}+\frac{1}{3\sqrt{2}+2\sqrt{3}}+...+\frac{1}{2016\sqrt{2015}+2015\sqrt{2016}}\le\frac{44}{45}\)
Chứng minh rằng
\(\frac{\sqrt[2016]{9}+\sqrt[2016]{16}+\sqrt[2016]{25}}{\sqrt[2016]{12}+\sqrt[2016]{15}+\sqrt[2016]{20}}>\frac{\sqrt[2017]{12}+\sqrt[2017]{15}+\sqrt[2017]{20}}{\sqrt[2017]{9}+\sqrt[2017]{16}+\sqrt[2017]{25}}\)
Tinh giá trị biểu thuc \(A=x^2+2016-2017\)
Biết \(x=\frac{\left(27+10\sqrt{2}\right)\sqrt{27-10\sqrt{2}}-\left(27-10\sqrt{2}\right)\sqrt{27+10\sqrt{2}}}{\left(\sqrt{\sqrt{13}-3}+\sqrt{\sqrt{13}+3}\right):\sqrt{\sqrt{13}+3}}\)
rút gọn biểu thức
A=2015+\(\sqrt{36}\)-\(\sqrt{25}\)
B=5\(\sqrt{8}\)+\(\sqrt{50}\)-2\(\sqrt{18}\)
C=\(\sqrt{27}\)-2\(\sqrt{12}\)-\(\sqrt{75}\)
D=\(\sqrt{12}\)+\(\sqrt{27}\)-\(\sqrt{48}\)
a: =2015+6-5=2016
b: =10căn 2+5căn 2-6căn 2=9căn 2
c: =3căn 3-4căn 3-5căn 3=-6căn 3
d: =2căn 3+3căn 3-4căn 3=căn 3
\(A=2015+6-5==2015+1=2016\)
\(B=5\sqrt{2^3}+\sqrt{5^2.2}-2\sqrt{3^2.2}\\ =10\sqrt{2}+5\sqrt{2}-6\sqrt{2}\\ =\left(10+5-6\right)\sqrt{2}=9\sqrt{2}\)
\(C=\sqrt{3^3}-2\sqrt{2^2.3}-\sqrt{5^2.3}\\ =3\sqrt{3}-4\sqrt{3}-5\sqrt{3}\\ =\left(3-4-5\right)\sqrt{3}=-6\sqrt{3}\)
\(D=\sqrt{2^2.3}+\sqrt{3^3}-\sqrt{4^2.3}\\ =2\sqrt{3}+3\sqrt{3}-4\sqrt{3}\\ =\left(2+3-4\right)\sqrt{3}=\sqrt{3}\)
\(\frac{\sqrt{44-15\sqrt{7}}+\sqrt{32-3\sqrt{7}}}{\sqrt{12-3\sqrt{7}}}-\sqrt{21-12\sqrt{3}}\) rút gọn biểu thức
Ket qua ra 3 nha, ban tinh tung ve roi tim hieu nhe
bạn có thể giải vế đầu giúp mình không
2.
a,\(\sqrt{12}-\sqrt{27}+\sqrt{3}\)
b,\(\sqrt{252}-\sqrt{700}+\sqrt{1008}-\sqrt{448};\sqrt{3}.\left(\sqrt{12}+\sqrt{27}-\sqrt{3}\right)\)
c,\(\frac{\sqrt{6}+\sqrt{10}}{\sqrt{21}+\sqrt{35}};\frac{\sqrt{405}+3\sqrt{27}}{3\sqrt{3}+\sqrt{45}}\)
d,\(\frac{\sqrt{2}+\sqrt{3}+\sqrt{4}-\sqrt{6}-\sqrt{9}-\sqrt{12}}{\sqrt{2}+\sqrt{3}+\sqrt{4}}\)
a)
\(\sqrt{12}-\sqrt{27}+\sqrt{3}=\sqrt{4}.\sqrt{3}-\sqrt{9}.\sqrt{3}+\sqrt{3}=2\sqrt{3}-3\sqrt{3}+\sqrt{3}\)
\(=\sqrt{3}(2-3+1)=0\)
b)
\(\sqrt{252}-\sqrt{700}+\sqrt{1008}-\sqrt{448}=\sqrt{4}.\sqrt{63}-\sqrt{4}.\sqrt{175}+\sqrt{4}.\sqrt{252}-\sqrt{4}.\sqrt{112}\)
\(=2(\sqrt{63}-\sqrt{175}+\sqrt{252}-\sqrt{112})\)
\(=2(\sqrt{9}.\sqrt{7}-\sqrt{25}.\sqrt{7}+\sqrt{36}.\sqrt{7}-\sqrt{16}.\sqrt{7})\)
\(=2(3\sqrt{7}-5\sqrt{7}+6\sqrt{7}-4\sqrt{7})=2\sqrt{7}(3-5+6-4)=0\)
------------------
\(\sqrt{3}(\sqrt{12}+\sqrt{27}-\sqrt{3})=\sqrt{36}+\sqrt{81}-\sqrt{9}\)
\(=\sqrt{6^2}+\sqrt{9^2}-\sqrt{3^2}=6+9-3=12\)
c)
\(\frac{\sqrt{6}+\sqrt{10}}{\sqrt{21}+\sqrt{35}}=\frac{\sqrt{2}.\sqrt{3}+\sqrt{2}.\sqrt{5}}{\sqrt{7}.\sqrt{3}+\sqrt{7}.\sqrt{5}}=\frac{\sqrt{2}(\sqrt{3}+\sqrt{5})}{\sqrt{7}(\sqrt{3}+\sqrt{5})}=\frac{\sqrt{2}}{\sqrt{7}}\)
\(\frac{\sqrt{405}+3\sqrt{27}}{3\sqrt{3}+\sqrt{45}}=\frac{\sqrt{81}.\sqrt{5}+3\sqrt{9}.\sqrt{3}}{3\sqrt{3}+\sqrt{9}.\sqrt{5}}=\frac{9\sqrt{5}+9\sqrt{3}}{3\sqrt{3}+3\sqrt{5}}\)
\(=\frac{3(3\sqrt{5}+3\sqrt{3})}{3\sqrt{3}+3\sqrt{5}}=3\)
d)
\(\frac{\sqrt{2}+\sqrt{3}+\sqrt{4}-\sqrt{6}-\sqrt{9}-\sqrt{12}}{\sqrt{2}+\sqrt{3}+\sqrt{4}}=\frac{\sqrt{2}+\sqrt{3}+\sqrt{4}-(\sqrt{6}+\sqrt{9}+\sqrt{12})}{\sqrt{2}+\sqrt{3}+\sqrt{4}}\)
\(=\frac{\sqrt{2}+\sqrt{3}+\sqrt{4}-(\sqrt{2}.\sqrt{3}+\sqrt{3}.\sqrt{3}+\sqrt{3}.\sqrt{4})}{\sqrt{2}+\sqrt{3}+\sqrt{4}}\)
\(=\frac{\sqrt{2}+\sqrt{3}+\sqrt{4}-\sqrt{3}(\sqrt{2}+\sqrt{3}+\sqrt{4})}{\sqrt{2}+\sqrt{3}+\sqrt{4}}=\frac{(\sqrt{2}+\sqrt{3}+\sqrt{4})(1-\sqrt{3})}{\sqrt{2}+\sqrt{3}+\sqrt{4}}=1-\sqrt{3}\)