Tính giá trị biểu thức :
\(A=\left(3\sqrt{3}\right)^{\frac{4}{3}}+\left(\frac{1}{16}\right)^{\frac{3}{4}}+2\left(\frac{8}{27}\right)^{\frac{2}{3}}\)
1/ Tính giá trị biểu thức
A=\(\frac{7}{35}+\left(-1\frac{3}{4}+\frac{12}{7}\right)-\left(\frac{1}{4}-\frac{2}{7}-\frac{13}{35}\right)-\frac{3}{7}\)\(\frac{3}{7}\)
B=\(\sqrt{\frac{25}{16}-\frac{\left(-3\right)^2}{\left|-4\right|}}+\frac{\sqrt{\left(-7\right)^2}}{4}-3.\left(\frac{5}{2}\right)^2\)
Bài 2. Tính giá trị biểu thức
a/ \(2\sqrt{27}-\sqrt{\frac{16}{3}}-\sqrt{48}-\sqrt{8\frac{1}{3}}\)
b/ \(\left(3\sqrt{20}-\sqrt{125}-15\sqrt{\frac{1}{5}}\right)\sqrt{5}\)
c/\(\left(2\sqrt{48}-\frac{3}{2}\sqrt{\frac{4}{3}}+\sqrt{27}\right).2\sqrt{3}\)
d/ \(\sqrt{\left(3-2\sqrt{2}\right)^2}-\sqrt{\left(\sqrt{8}-4\right)^2}\)
e/ \(\sqrt{\left(4-\sqrt{15}\right)^2}+\sqrt{\left(3-\sqrt{15}\right)^2}\)
Tính giá trị biểu thức :
\(M=\left(\frac{1}{4}\right)^{-\frac{3}{2}}-2\left(\frac{125}{27}\right)^{-\frac{2}{3}}+2^{\left(\sqrt{6}+\sqrt{2}\right)\sqrt{2-\sqrt{3}}}\)
Ta có:
\(\left(\frac{1}{4}\right)^{-\frac{3}{2}}=8\) ;
\(2\left(\frac{125}{27}\right)^{-\frac{2}{3}}=2.\frac{9}{25}=\frac{18}{25}\) ;
\(\left(\sqrt{6}+\sqrt{2}\right)\sqrt{2-\sqrt{3}}=2\Rightarrow2^{\left(\sqrt{6}+\sqrt{2}\right)\sqrt{2-\sqrt{3}}}=2^2=4\)
\(\Rightarrow M=8-\frac{18}{25}+4=4\frac{18}{25}\)
Ta có \(\left(\sqrt{6}+\sqrt{2}\right)\sqrt{2-\sqrt{3}}=\left(\sqrt{3}+1\right)\sqrt{4-2\sqrt{3}}=\left(\sqrt{3}+1\right)\left(\sqrt{3}-1\right)=2\)
Nên \(B=2^{2\left(-\frac{3}{2}\right)}-2\left(\frac{5}{3}\right)^{3\left(-\frac{2}{3}\right)}+2^2=2^3-2\left(\frac{3}{5}\right)^2+4=\frac{282}{25}\)
Tính giá trị biểu thức
1, \(\frac{1}{16}-\frac{5}{21}+\left(\frac{-1}{16}+\frac{-3}{5}-\frac{-5}{21}\right)+\frac{-2}{3}+\frac{3}{4}\)
2, \(\left(\frac{5}{8}-\frac{4}{13}+\frac{3}{2}\right)-\left(\frac{5}{8}+\frac{9}{13}\right)-\left|\frac{-3}{2}\right|+\frac{-7}{15}\)
Tính giá trị biểu thức: Q=\(\frac{\left(\frac{-1}{2}\right)^3-\left(\frac{3}{4}\right)^3.\left(-2\right)^2}{2.\left(-1\right)^5+\left(\frac{3}{4}\right)^2-\frac{3}{8}}\)
\(=\frac{-\frac{1}{8}-\frac{27}{64}.4}{-2+\frac{9}{16}-\frac{3}{8}}\)
\(=\frac{-\frac{1}{8}-\frac{27}{16.4}.4}{-2+\frac{9-6}{16}}\)
\(=\frac{-\frac{1}{8}-\frac{27}{16}}{-2+\frac{3}{16}}\)
\(=\frac{-\left(\frac{2+27}{16}\right)}{\frac{-32+3}{16}}\)
\(=\frac{-\frac{29}{16}}{\frac{-29}{16}}\)
\(=1\)
Tính giá trị các biểu thức sau:
a) \(\sqrt[4]{{\frac{1}{{16}}}}\);
b) \({\left( {\sqrt[6]{8}} \right)^2}\);
c) \(\sqrt[4]{3}.\sqrt[4]{{27}}\).
a) \(\sqrt[4]{\dfrac{1}{16}}=\dfrac{1}{2}\)
b) \(\left(\sqrt[6]{8}\right)^2=\sqrt[\dfrac{6}{2}]{8}=\sqrt[3]{8}=2\)
c) \(\sqrt[4]{3}\cdot\sqrt[4]{27}=\sqrt[4]{3\cdot27}=\sqrt[4]{81}=3\)
Cho biểu thức: \(A = \left( {2 + \frac{1}{3} - \frac{2}{5}} \right) - \left( {7 - \frac{3}{5} - \frac{4}{3}} \right) - \left( {\frac{1}{5} + \frac{5}{3} - 4} \right).\)
Hãy tính giá trị của A theo hai cách:
a) Tính giá trị của từng biểu thức trong dấu ngoặc trước.
b) Bỏ dấu ngoặc rồi nhóm các số hạng thích hợp.
a)
\(\begin{array}{l}A = \left( {2 + \frac{1}{3} - \frac{2}{5}} \right) - \left( {7 - \frac{3}{5} - \frac{4}{3}} \right) - \left( {\frac{1}{5} + \frac{5}{3} - 4} \right).\\A = \left( {\frac{{30}}{{15}} + \frac{5}{{15}} - \frac{6}{{15}}} \right) - \left( {\frac{{105}}{{15}} - \frac{9}{{15}} - \frac{{20}}{{15}}} \right) - \left( {\frac{3}{{15}} + \frac{{25}}{{15}} - \frac{{60}}{{15}}} \right)\\A = \frac{{29}}{{15}} - \frac{{76}}{{15}} - \left( {\frac{{ - 32}}{{15}}} \right)\\A = \frac{{29}}{{15}} - \frac{{76}}{{15}} + \frac{{32}}{{15}}\\A = \frac{{ - 15}}{{15}}\\A = - 1\end{array}\)
b)
\(\begin{array}{l}A = \left( {2 + \frac{1}{3} - \frac{2}{5}} \right) - \left( {7 - \frac{3}{5} - \frac{4}{3}} \right) - \left( {\frac{1}{5} + \frac{5}{3} - 4} \right)\\A = 2 + \frac{1}{3} - \frac{2}{5} - 7 + \frac{3}{5} + \frac{4}{3} - \frac{1}{5} - \frac{5}{3} + 4\\A = \left( {2 - 7 + 4} \right) + \left( {\frac{1}{3} + \frac{4}{3} - \frac{5}{3}} \right) + \left( { - \frac{2}{5} + \frac{3}{5} - \frac{1}{5}} \right)\\A = - 1 + 0 + 0 = - 1\end{array}\)
tính giá trị của biểu thức M=\(1+\frac{1}{2}.\left(1+2\right)+\frac{1}{3}.\left(1+2+3\right)+\frac{1}{4}.\left(1+2+3+4\right)+...+\frac{1}{16}.\left(1+2+3+...+16\right)\)
Tính giá trị của các biểu thức sau:
\(\begin{array}{l}a)\left( {\frac{2}{3} + \frac{1}{6}} \right):\frac{5}{4} + \left( {\frac{1}{4} + \frac{3}{8}} \right):\frac{5}{2}\\b)\frac{5}{9}:\left( {\frac{1}{{11}} - \frac{5}{{22}}} \right) + \frac{7}{4}.\left( {\frac{1}{{14}} - \frac{2}{7}} \right)\end{array}\)
\(\begin{array}{l}a)\left( {\frac{2}{3} + \frac{1}{6}} \right):\frac{5}{4} + \left( {\frac{1}{4} + \frac{3}{8}} \right):\frac{5}{2}\\ = \left( {\frac{4}{6} + \frac{1}{6}} \right).\frac{4}{5} + \left( {\frac{2}{8} + \frac{3}{8}} \right).\frac{2}{5}\\ = \frac{5}{6}.\frac{4}{5} + \frac{5}{8}.\frac{2}{5}\\ = \frac{2}{3} + \frac{1}{4}\\ = \frac{8}{{12}} + \frac{3}{{12}}\\ = \frac{{11}}{{12}}\\b)\frac{5}{9}:\left( {\frac{1}{{11}} - \frac{5}{{22}}} \right) + \frac{7}{4}.\left( {\frac{1}{{14}} - \frac{2}{7}} \right)\\ = \frac{5}{9}:\left( {\frac{2}{{22}} - \frac{5}{{22}}} \right) + \frac{7}{4}.\left( {\frac{1}{{14}} - \frac{4}{{14}}} \right)\\ = \frac{5}{9}:\frac{{ - 3}}{{22}} + \frac{7}{4}.\frac{{ - 3}}{{14}}\\ = \frac{5}{9}.\frac{{ - 22}}{3} + \frac{{ - 3}}{8}\\ = \frac{{ - 110}}{{27}} + \frac{{ - 3}}{8}\\ = \frac{{ - 880}}{{216}} + \frac{{ - 81}}{{216}}\\ = \frac{{ - 961}}{{216}}\end{array}\)