ĐKXĐ: 25-x2>=0
=>(x-5)(x+5)<=0
=>-5<=x<=5
ĐKXĐ: 25-x2>=0
=>(x-5)(x+5)<=0
=>-5<=x<=5
\(\left(\dfrac{x-5\sqrt{x}}{x-25}-1\right):\left(\dfrac{25-x}{x+2\sqrt{x}-15}-\dfrac{\sqrt{x}+3}{\sqrt{x}+5}+\dfrac{\sqrt{x}-5}{\sqrt{x}-3}\right)\)
rút gọn:
\(\frac{1}{2\sqrt{1}+1\sqrt{2}}+\frac{1}{3\sqrt{2}+2\sqrt{3}}+\frac{1}{4\sqrt{3}+3\sqrt{4}}+....+\frac{1}{25\sqrt{24}+24\sqrt{25}}\)
Rút gọn : C= \(\left(\dfrac{x-5\sqrt{x}}{x-25}-1\right):\left(\dfrac{25-x}{x+2\sqrt{x}-15}-\dfrac{\sqrt{x}+3}{\sqrt{x}+5}+\dfrac{\sqrt{x}-5}{\sqrt{x}-3}\right)\)
\(\sqrt{\sqrt{5}-\sqrt{3-\sqrt{25-12\sqrt{5}}}}\)
Thực hiện phép tính:
a. \(\sqrt{25}+2\sqrt{49}\)
b. \(\sqrt{16}.\sqrt{25}+\sqrt{169}:\sqrt{49}\)
c. \(\sqrt{\left(3-\sqrt{7}\right)^2}+\sqrt{7}\)
d. \(2\sqrt{3}-\sqrt{75}+2\sqrt{12}\)
Tính tổng S=\(\sqrt{0,49}+\sqrt{\dfrac{1}{9}}-\sqrt{\dfrac{25}{4}}\)
rút gọn biểu thức
K=\(\dfrac{1}{2\sqrt{1}+1\sqrt{2}}+\dfrac{1}{3\sqrt{2}+2\sqrt{3}}+...+\dfrac{1}{25\sqrt{24}+24\sqrt{25}}\)
M=\(\dfrac{2+\sqrt{3}}{\sqrt{2}+\sqrt{2+\sqrt{3}}}+\dfrac{2-\sqrt{3}}{\sqrt{2}-\sqrt{2-\sqrt{3}}}\)
N=\(\dfrac{1+\sqrt{5}}{\sqrt{2}+\sqrt{3+\sqrt{5}}}+\dfrac{1-\sqrt{5}}{\sqrt{2}-\sqrt{3-\sqrt{5}}}\)
a, \(\sqrt{1\frac{24}{25}.5\frac{1}{16}.0,01}=\sqrt{\frac{49}{25}.\frac{81}{16}.\frac{1}{100}}\)
b, \(\sqrt{2,25.1,46-2,25.0,02}\)
A=\(\left(\frac{x-5\sqrt{x}}{x-25}-1\right):\left(\frac{25-x}{x+2\sqrt{x}-15}-\frac{\sqrt{x}+3}{\sqrt{x}+5}+\frac{\sqrt{x}-5}{\sqrt{x-3}}\right)\)
a,Rút gọn A
b,Tính giá trị của A khi x=29-12\(\sqrt{5}\)
Cho 25 số tự nhiên bất kỳ a1, a2, a3,..., a25 thỏa mãn :
\(\dfrac{1}{\sqrt{a_1}}+\dfrac{1}{\sqrt{a_2}}+\dfrac{1}{\sqrt{a_3}}+...+\dfrac{1}{\sqrt{a_{25}}}=9\)
Trong 25 số đó có ít nhất 2 số bằng nhau.