\(M=\sqrt{15a^2-8a\sqrt{15}+16}=\sqrt{\left(\sqrt{15}a-4\right)^2}\)
\(=\sqrt{15}a-4=\sqrt{15}\left(\sqrt{\frac{3}{5}}+\sqrt{\frac{5}{3}}\right)-4\)
\(=\left(3+5\right)-4=4\)
\(M=\sqrt{15a^2-8a\sqrt{15}+16}=\sqrt{\left(\sqrt{15}a-4\right)^2}\)
\(=\sqrt{15}a-4=\sqrt{15}\left(\sqrt{\frac{3}{5}}+\sqrt{\frac{5}{3}}\right)-4\)
\(=\left(3+5\right)-4=4\)
Cho a= \(\sqrt{\frac{3}{5}}+\sqrt{\frac{5}{3}}\) Hãy tính giá trị của biểu thức sau :
M = \(\sqrt{15a^2-8a\sqrt{15}+16}\)
3. Tính giá trị của biểu thức
A=\(\sqrt{5a^2-4\sqrt{5a}+4}\) Tại \(a=\sqrt{5}+\frac{1}{\sqrt{5}}\)
B= \(\sqrt{15a^2-8a\sqrt{15}+16}\) Với \(a=\sqrt{\frac{3}{5}}+\sqrt{\frac{5}{3}}\)
C= \(\sqrt{x^2+2\sqrt{x^2-1}}-\sqrt{x^2-2\sqrt{x^2-1}}\) Tại \(x=\sqrt{5}\)
a)\(\frac{4}{\sqrt{5}-1}+\frac{3}{\sqrt{5}-2}+\frac{16}{\sqrt{5}-3}\)
b)\(\frac{2}{\sqrt{8-2\sqrt{15}}}-\frac{1}{\sqrt{5-2\sqrt{6}}}-\frac{3}{\sqrt{7+2\sqrt{10}}}\)
c)\(\frac{8+2\sqrt{2}}{3-\sqrt{2}}-\frac{2+3\sqrt{2}}{\sqrt{2}}+\frac{\sqrt{2}}{1-\sqrt{2}}\)
d)\(\sqrt{1+\frac{\sqrt{3}}{2}}-\frac{\sqrt{8-\sqrt{15}}}{\sqrt{30}-\sqrt{2}}\)
ai làm nhanh giúp em với
a) P=\(\frac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\frac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}\)
b) Q=\(\frac{3+2\sqrt{3}}{\sqrt{3}}+\frac{2+\sqrt{2}}{\sqrt{2}+1}-\left(\sqrt{2}+\sqrt{3}\right)\)
c) M=\(\left(\frac{2}{\sqrt{3}-1}+\frac{3}{\sqrt{3}-2}+\frac{15}{3-\sqrt{3}}\right).\frac{1}{\sqrt{3}+5}\)
d) N=\(\left(\frac{\sqrt{14}-\sqrt{7}}{1-\sqrt{2}}+\frac{\sqrt{15}-\sqrt{5}}{1-\sqrt{3}}\right):\frac{1}{\sqrt{7}-\sqrt{5}}\)
Cho \(x=\sqrt{6+2\sqrt{2}.\left(\sqrt{\frac{5}{2}-\sqrt{6}+\sqrt{\left(3\sqrt{a}+1\right)\left(2a-2\right)-\frac{6a^2+6\sqrt{a}-8a-4a\sqrt{a}}{\sqrt{a}-1}+8}}\right)}\) với a là số thực không âm
\(y=\frac{\frac{x-2}{x}+\frac{1}{x-2}}{12-8\sqrt{5}}.\left(-16\right)\)
So sánh x và y
Rút gọn biểu thức
1)\(\frac{15}{3\sqrt{20}}\)
2) \(\frac{\sqrt{15}-\sqrt{6}}{\sqrt{2}-\sqrt{5}}\)
3) \(\frac{3}{\sqrt{5}-\sqrt{2}}+\frac{4}{\sqrt{6}+\sqrt{2}}\)
4) \(\sqrt{\frac{3}{20}}+\sqrt{\frac{1}{60}}-2\sqrt{\frac{1}{15}}\)
5) \(\left(\sqrt{20}-\sqrt{45}+\sqrt{5}\right)\sqrt{5}\)
6)\(\left(2+\sqrt{5}\right)^2-\left(2+\sqrt{5}\right)^2\)
7) \(\left(5\sqrt{\frac{1}{5}}+\frac{1}{2}\sqrt{20}-\frac{5}{4}\sqrt{\frac{4}{5}+\sqrt{5}}\right):2\sqrt{5}\)
8)\(\frac{1}{3}\sqrt{48}+3\sqrt{75}-\sqrt{27}-10\sqrt{1\frac{1}{3}}\)
9) \(2\sqrt{3}\left(2\sqrt{6}-\sqrt{3}+1\right)\)
10) \(\left(5\sqrt{3}+3\sqrt{5}\right):\sqrt{15}\)
11) \(\sqrt{\sqrt{10}+1}.\sqrt{\sqrt{10}-1}\)
12) \(\frac{5\sqrt{7}-7\sqrt{5}+2\sqrt{70}}{\sqrt{35}}\)
13) \(\sqrt{\frac{3}{4}}+\sqrt{\frac{1}{3}}+\sqrt{\frac{1}{12}}\)
14) \(\left(\sqrt{\frac{2}{3}}+\sqrt{\frac{3}{2}}\right)\sqrt{6}\)
15 ) \(\sqrt{\frac{4}{3}}+\sqrt{12}-\frac{4}{3}\sqrt{\frac{3}{4}}\)
16) \(\frac{1}{\sqrt{5}+\sqrt{3}}-\frac{1}{\sqrt{5}-\sqrt{3}}\)
17) \(\frac{1}{2+\sqrt{3}}+\frac{\sqrt{2}}{\sqrt{6}}-\frac{2}{3+\sqrt{3}}\)
tính:
a)\(\frac{1}{1+\sqrt{5}}+\frac{1}{1-\sqrt{5}}\)
b)\(\frac{\sqrt{15}-\sqrt{12}}{\sqrt{5}-2}+\frac{1}{2-\sqrt{3}}\)
c)\(\frac{2}{\sqrt{5}+1}+\sqrt{\frac{2}{3-\sqrt{5}}}-5\sqrt{\frac{1}{5}}\)
d)\(\left(\frac{5}{\sqrt{15}-\sqrt{10}}-\frac{3\sqrt{5}-5\sqrt{3}}{\sqrt{3}-\sqrt{5}}\right)^2\)
e)\(\frac{2}{\sqrt{3}-\sqrt{5}}+\frac{3-2\sqrt{3}}{\sqrt{3}-2}\)
THỰC HIỆN PHÉP TÌNH VÀ RÚT GỌN CÁC BIỂU THỨC:
A=\(\left(\sqrt{\frac{2}{3}}+\sqrt{\frac{50}{3}}-\sqrt{24}\right).\)\(\sqrt{6}\)
B= \(\left(\frac{\sqrt{14}-\sqrt{7}}{\sqrt{2}-1}+\frac{\sqrt{15}-\sqrt{5}}{\sqrt{3}-1}\right)\)\(:\frac{1}{\sqrt{7}-\sqrt{5}}\)
Bài 1: Tìm điều kiện xác đinh của các biểu thức sau
a, A=\(\frac{x-1}{\sqrt{x-1}}+\sqrt{2x+5}\)
b, B=\(\frac{\sqrt{-x}}{x^2-3}-2019\)
Bài 2: Rút gọn
a, A=\(\frac{15-9\sqrt{2}}{5\sqrt{5}-3\sqrt{10}}-\sqrt{\frac{16}{5}}-\frac{1}{\sqrt{10}+\sqrt{5}}\)
b, B=\(\frac{\sqrt{145\sqrt{154}}-\sqrt{9-\sqrt{77}}}{1-\frac{1}{\sqrt{2}}}\)