Tính:
\(a)\sqrt {64} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,b)\sqrt {{{25}^2}} ;\,\,\,\,\,\,\,\,\,\,\,c)\sqrt {{{\left( { - 5} \right)}^2}} .\)
Giá trị biểu thức A = [ \(\sqrt{64}\) + 2.\(\sqrt{(-3)^{2}}\)- 7.\(\sqrt{1,69}\) + 3.\(\sqrt{\dfrac{25}{16}}\)] : (5.\(\sqrt{\dfrac{2}{3}})^{2}\)
Tính A. Các bạn giúp mk với ạ.
\(A=\left(8+2\cdot3-7\cdot\dfrac{13}{10}+3\cdot\dfrac{5}{4}\right):\left(\dfrac{5\sqrt{6}}{3}\right)^2\\ A=\left(14-\dfrac{91}{10}+\dfrac{15}{4}\right):\dfrac{50}{3}\\ A=\dfrac{173}{20}\cdot\dfrac{3}{50}=\dfrac{519}{1000}\)
Tính
a) \(2\sqrt{\frac{25}{16}}-3\sqrt{\frac{49}{36}}+4\sqrt{\frac{81}{64}}\)
b) \(\left(3\sqrt{2}\right)^2-\left(4\sqrt{\frac{1}{2}}\right)^2+\frac{1}{16}.\left(\sqrt{\frac{3}{4}}\right)^2\)
c) \(\frac{2}{3}\sqrt{\frac{81}{16}}-\frac{3}{4}\sqrt{\frac{64}{9}}+\frac{7}{5}.\sqrt{\frac{25}{196}}\)
a) = \(\frac{7}{2}\)
b) = \(\frac{643}{64}\)
c) = 0
B1, Tính a, \(\sqrt{\left(2-\sqrt{5}\right)^2}-\sqrt{5}\)
b, \(\sqrt{16}.\sqrt{25}+\sqrt{256}.\sqrt{64}\)
c,\(\sqrt{\left(\sqrt{2}-3\right)^2}-\sqrt{\left(5-\sqrt{2}\right)^2}\)
a,\(\sqrt{\left(2-\sqrt{5}\right)^2}-\sqrt{5}\)
\(=|^{ }_{ }2-\sqrt{5}|^{ }_{ }-\sqrt{5}\)
\(=\sqrt{5}-2-\sqrt{5}\)(vì \(2-\sqrt{5}< 0\))
=-2
b,\(\sqrt{16}\cdot\sqrt{25}+\sqrt{256}\cdot\sqrt{64}\)
\(=4\cdot5-16\cdot8=20+128=148\)
c,\(\sqrt{\left(\sqrt{2}-3\right)^2}-\sqrt{\left(5-\sqrt{2}\right)^2}\)
\(=|^{ }_{ }\sqrt{2}-3|^{ }_{ }-|^{ }_{ }5-\sqrt{2}|^{ }_{ }\)
\(=3-\sqrt{2}-5+\sqrt{2}\)(vì \(\sqrt{2}-3< 0;5-\sqrt{2}>0\))
\(=-2\)
à bạn ơi , mình không hiểu câu c gì à , bạn làm ơn viết lại mình xem,
Tính A= \(\left[\sqrt{64}+2.\sqrt{\left(-3\right)^2}-7.\sqrt{1,69}+3.\sqrt{\frac{25}{16}}\right]:\left(5.\sqrt{\frac{2}{3}}\right)^2\)
Thực hiện phép tính:
a) \(\sqrt{36}.\sqrt{121}+\sqrt[3]{-64}-\sqrt[3]{125}\)
b) \(\sqrt{75}+\sqrt{\left(\sqrt{3}-2\right)^2}-30\sqrt{\frac{3}{25}}\)
c) \(\sqrt{11-4\sqrt{7}}-\frac{12}{1+\sqrt{7}}\)
a) \(\sqrt{36}.\sqrt{121}+\sqrt[3]{-64}-\sqrt[3]{125}\)
\(=6.11+\left(-4\right)-5=66-9=57\)
b) \(\sqrt{75}+\sqrt{\left(\sqrt{3}-2\right)^2}-30\sqrt{\frac{3}{25}}\)
\(=\sqrt{25.3}+\left|\sqrt{3}-2\right|-30.\frac{\sqrt{3}}{\sqrt{25}}\)
\(=5\sqrt{3}+2-\sqrt{3}-30.\frac{\sqrt{3}}{5}\)
\(=5\sqrt{3}+2-\sqrt{3}-6\sqrt{3}=2-2\sqrt{3}\)
c) \(\sqrt{11-4\sqrt{7}}-\frac{12}{1+\sqrt{7}}=\sqrt{7-4\sqrt{7}+4}-\frac{12}{1+\sqrt{7}}\)
\(=\sqrt{\left(\sqrt{7}-2\right)^2}-\frac{12}{1+\sqrt{7}}=\left|\sqrt{7}-2\right|-\frac{12}{1+\sqrt{7}}\)
\(=\left(\sqrt{7}-2\right)-\frac{12}{\sqrt{7}+1}=\frac{\left(\sqrt{7}-2\right)\left(\sqrt{7}+1\right)}{\sqrt{7}+1}-\frac{12}{\sqrt{7}+1}\)
\(=\frac{5-\sqrt{7}}{\sqrt{7}+1}-\frac{12}{\sqrt{7}+1}=\frac{-7-\sqrt{7}}{\sqrt{7}+1}\)
\(=\frac{-\sqrt{7}\left(\sqrt{7}+1\right)}{\sqrt{7}+1}=-\sqrt{7}\)
bài 1 So sánh
a, \(\sqrt{50}+\sqrt{39}+3\) và 16
b, \(\sqrt{3}+\sqrt{8}+2\) và 7
c, \(2\sqrt{26}+3\sqrt{64}-5\) và 28
bài 2 Tính nhanh
a, \(\sqrt{4}+\sqrt{25}+\sqrt{64}+...+\sqrt{2500}\)
b, \(\sqrt{1}+\sqrt{25}+\sqrt{81}+...+\sqrt{9409}\)
c, \(\sqrt{\frac{1}{4}}+\sqrt{\frac{1}{36}}+\sqrt{\frac{1}{144}}+...+\sqrt{\frac{1}{9900^2}}\)
Bài 2:
a) Ta có: \(\sqrt{4}+\sqrt{25}+\sqrt{64}+...+\sqrt{2500}\)
\(=2+5+8+...+50\)
Số hạng tử là: \(\frac{50-2}{3}+1=\frac{48}{3}+1=16+1=17\)(số)
Tổng của dãy số là: \(\left(50+2\right)\cdot\frac{17}{2}=\frac{52\cdot17}{2}=26\cdot17=442\)
b) Ta có: \(\sqrt{1}+\sqrt{25}+\sqrt{81}+...+\sqrt{9409}\)
\(=1+5+9+...+97\)
Số hạng tử là:
\(\frac{97-1}{4}+1=\frac{96}{4}+1=24+1=25\)(số)
Tổng của dãy số là: \(\left(97+1\right)\cdot\frac{25}{2}=\frac{98\cdot25}{2}=49\cdot25=1225\)
Giúp mik với
Tính
a)\(\frac{2}{3}\sqrt{81}-\left(\frac{-3}{4}\right).\sqrt{\frac{9}{64}}+\left(\frac{\sqrt{2}}{3}\right)^2\)
b)\(\left(-\sqrt{\frac{5}{4}}\right)^2-\sqrt{\frac{9}{4}}:\left(-4,5\right)-\sqrt{\frac{25}{16}}.\sqrt{\frac{64}{9}}\)
c)\(-2^4-\left(-2\right)^2:\left(-\sqrt{\frac{16}{121}}\right)-\left(-\sqrt{\frac{2}{3}}\right)^2:\left(-2\frac{2}{3}\right)\)
a
\(\sqrt{25-3\sqrt{\frac{4}{3}}}\)
b\(\left(-2^3\right)+\frac{1}{2}:\frac{1}{8}-\sqrt{25}+\left|-64\right|\)
c\(\left(-2^2\right)+\sqrt{36}.2-\sqrt{9}.3+\sqrt{25}\)
Bài 2: Tính:
a.\(\sqrt{81}\)
b. \(\sqrt{8100}\)
c. \(\sqrt{64}\)
d. \(\sqrt{\dfrac{49}{100}}\)
e . \(\sqrt{\dfrac{4}{25}}\)