Các câu hỏi tương tự
c1: \(\frac{1}{2}-\left(\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+...+\frac{1}{1+2+3+...+x}\right)=-\frac{503}{1008}\)
Bài 1: Tính giá trị biểu thức A frac{frac{1}{2}+frac{1}{3}+frac{1}{4}+...+frac{1}{2018}}{frac{2017}{1}+frac{2016}{2}+frac{2015}{3}+...+frac{1}{2017}}B frac{frac{1}{51}+frac{1}{53}+frac{1}{55}+...+frac{1}{149}}{frac{1}{101.99}+frac{1}{103.97}+...+frac{1}{149.51}}C frac{1+frac{1}{3}+frac{1}{5}+...+frac{1}{99}}{frac{1}{1.99}+frac{1}{3.97}+...+frac{1}{99.1}}D frac{frac{1}{1.300}+frac{1}{2.301}+frac{1}{3.302}+...+frac{1}{101.400}}{frac{1}{1.102}+frac{1}{2.103}+frac{1}{3.104}+...+frac{1}{299.4000}} ...
Đọc tiếp
Bài 1: Tính giá trị biểu thức
A= \(\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2018}}{\frac{2017}{1}+\frac{2016}{2}+\frac{2015}{3}+...+\frac{1}{2017}}\)
B= \(\frac{\frac{1}{51}+\frac{1}{53}+\frac{1}{55}+...+\frac{1}{149}}{\frac{1}{101.99}+\frac{1}{103.97}+...+\frac{1}{149.51}}\)
C= \(\frac{1+\frac{1}{3}+\frac{1}{5}+...+\frac{1}{99}}{\frac{1}{1.99}+\frac{1}{3.97}+...+\frac{1}{99.1}}\)
D= \(\frac{\frac{1}{1.300}+\frac{1}{2.301}+\frac{1}{3.302}+...+\frac{1}{101.400}}{\frac{1}{1.102}+\frac{1}{2.103}+\frac{1}{3.104}+...+\frac{1}{299.4000}}\)
Bài 2: Tìm x, biết:
a) \(\frac{x+1}{2014}+\frac{x+2}{2013}+...+\frac{x+1007}{1008}=\frac{x+1008}{1007}+\frac{x+1009}{1006}+...+\frac{x+2014}{1}\)
b) \(\frac{2}{\left(x-1\right)\left(x-3\right)}+\frac{5}{\left(x-3\right)\left(x-8\right)}+\frac{12}{\left(x-8\right)\left(x-20\right)}-\frac{1}{x-20}=\frac{-1}{4}\)
Các bạn làm hết giúp mik nha! ^ ^
Tìm x biết frac{x+2}{327}+frac{x+3}{326}+frac{x+4}{325}+frac{x+5}{324}+frac{x+349}{5}0CMR:frac{1}{2!}+frac{2}{3!}+frac{3}{4!}+...+frac{99}{100!} 1frac{1}{sqrt{1}}+frac{1}{sqrt{2}}+frac{1}{sqrt{3}}+...+frac{1}{sqrt{100}}10Tính B1+frac{1}{2}left(1+2right)+frac{1}{3}left(1+2+3right)+frac{1}{4}left(1+2+3+4right)+...+frac{1}{20}left(1+2+3+...+20right)
Đọc tiếp
Tìm x biết \(\frac{x+2}{327}+\frac{x+3}{326}+\frac{x+4}{325}+\frac{x+5}{324}+\frac{x+349}{5}=0\)
CMR:\(\frac{1}{2!}+\frac{2}{3!}+\frac{3}{4!}+...+\frac{99}{100!}< 1\)
\(\frac{1}{\sqrt{1}}+\frac{1}{\sqrt{2}}+\frac{1}{\sqrt{3}}+...+\frac{1}{\sqrt{100}}>10\)
Tính \(B=1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+\frac{1}{4}\left(1+2+3+4\right)+...+\frac{1}{20}\left(1+2+3+...+20\right)\)
Tìm x, biết:a)-3frac{1}{2}+frac{1}{3}.left(x-1right)-1frac{1}{3}:2frac{1}{3}b)frac{x-1}{4}frac{x-2}{5}c)frac{x}{0,04}frac{0,09}{x}d)4:left(x-1right)left(x-1right):9e)3frac{1}{2}:x.frac{1}{2}5frac{1}{3}:frac{1}{2}.frac{1}{5}f)/2x-3/5g)left(2x-frac{1}{3}right)^2left(13xright)^2h) left(3-frac{1}{2}:xright)^2frac{1}{4}i) left(3-1frac{1}{2}:xright)^3frac{1}{8}
Đọc tiếp
Tìm x, biết:
a)\(-3\frac{1}{2}+\frac{1}{3}.\left(x-1\right)=-1\frac{1}{3}:2\frac{1}{3}\)
b)\(\frac{x-1}{4}=\frac{x-2}{5}\)
c)\(\frac{x}{0,04}=\frac{0,09}{x}\)
d)\(4:\left(x-1\right)=\left(x-1\right):9\)
e)\(3\frac{1}{2}:x.\frac{1}{2}=5\frac{1}{3}:\frac{1}{2}.\frac{1}{5}\)
f)/2x-3/=5
g)\(\left(2x-\frac{1}{3}\right)^2=\left(1=3x\right)^2\)
h) \(\left(3-\frac{1}{2}:x\right)^2=\frac{1}{4}\)
i) \(\left(3-1\frac{1}{2}:x\right)^3=\frac{1}{8}\)
Bài 1 : Thực hiện phép tính(1) D 1+frac{1}{2}left(1+2right)+frac{1}{3}left(1+2+3right)+...+frac{1}{16}left(1+2+...+16right)(2) M frac{frac{1}{99}+frac{2}{98}+frac{3}{97}+...+frac{99}{1}}{frac{1}{2}+frac{1}{3}+frac{1}{4}+...+frac{1}{100}}Bài 2 : Tìm x biết(1) x-left{x-left[x-left(-x+1right)right]right}1(2) left[frac{1}{2}+frac{1}{3}+...+frac{1}{2016}right]cdot xfrac{2015}{1}+frac{2014}{2}+...+frac{1}{2015}(3) frac{x}{left(a+5right)left(4-aright)}frac{1}{a+5}+frac{1}{4-a}(4) frac{x+2}{11}+frac{x+...
Đọc tiếp
Bài 1 : Thực hiện phép tính
(1) D = \(1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+...+\frac{1}{16}\left(1+2+...+16\right)\)
(2) M =\(\frac{\frac{1}{99}+\frac{2}{98}+\frac{3}{97}+...+\frac{99}{1}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)
Bài 2 : Tìm x biết
(1) \(x-\left\{x-\left[x-\left(-x+1\right)\right]\right\}=1\)
(2) \(\left[\frac{1}{2}+\frac{1}{3}+...+\frac{1}{2016}\right]\cdot x=\frac{2015}{1}+\frac{2014}{2}+...+\frac{1}{2015}\)
(3) \(\frac{x}{\left(a+5\right)\left(4-a\right)}=\frac{1}{a+5}+\frac{1}{4-a}\)
(4) \(\frac{x+2}{11}+\frac{x+2}{12}+\frac{x+2}{13}=\frac{x+2}{14}+\frac{x+2}{15}\)
(5) \(\frac{x+1}{2015}+\frac{x+2}{2014}+\frac{x+3}{2013}+\frac{x+4}{2012}+4=0\)
Bài 3 :
(1) Cho : A =\(\frac{9}{1}+\frac{8}{2}+\frac{7}{3}+...+\frac{1}{9}\); B =\(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{10}\)
CMR : \(\frac{A}{B}\)Là 1 số nguyên
(2) Cho : D =\(\frac{1}{1001}+\frac{1}{1002}+\frac{1}{1003}+...+\frac{1}{2000}\)CMR : \(D< \frac{3}{4}\)
Bài 4 : Ký hiệu [x] là số nguyên lớn nhất không vượt quá x , gọi là phần nguyên của x.
VD : [1.5] =1 ; [3] =3 ; [-3.5] = -4
(1) Tính :\(\left[\frac{100}{3}\right]+\left[\frac{100}{3^2}\right]+\left[\frac{100}{3^3}\right]+\left[\frac{100}{3^4}\right]\)
(2) So sánh : A =\(\left[X\right]+\left[X+\frac{1}{5}\right]+\left[X+\frac{2}{5}\right]+\left[X+\frac{3}{5}\right]+\left[X+\frac{4}{5}\right]\)và B = [5x]. Biết x=3.7
tìm x
\(\frac{4}{5}x^2\left(\frac{x}{3}-\frac{1}{2}\right)-\left(\frac{1}{2}x-\frac{2}{3}\right)\left(\frac{4x^2}{3}+1\right)=\frac{22}{45}x^2\)
1.Tìm x biếta) left(frac{2}{5}-xright):1frac{1}{3}+frac{1}{2}-4b) left(-3+frac{3}{x}-frac{1}{3}right):left(1+frac{2}{5}+frac{2}{3}right)-frac{5}{4}c) frac{-3x}{4}.left(frac{1}{x}+frac{2}{7}right)0d) 3-frac{1-frac{1}{2}}{1+frac{1}{x}}2frac{2}{3}e)left(2x+frac{1}{3}right)^2frac{9}{16}f) 4^x+4^{x+3}4160g) left(x-2,5right):1frac{1}{2}x:2h) left(frac{1}{3}+xright):left(x+frac{3}{4}right)frac{7}{9}i) 0,81:frac{x}{2}frac{16}{x^4}:left(-0,9right)2. Tìm x, biết:a)left(152frac{2}{4}-148frac{3}{8}right):0,...
Đọc tiếp
1.Tìm x biết
a) \(\left(\frac{2}{5}-x\right)\):\(1\frac{1}{3}+\frac{1}{2}=-4\)
b) \(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\left(1+\frac{2}{5}+\frac{2}{3}\right)=-\frac{5}{4}\)
c) \(\frac{-3x}{4}.\left(\frac{1}{x}+\frac{2}{7}\right)=0\)
d) 3-\(\frac{1-\frac{1}{2}}{1+\frac{1}{x}}=2\frac{2}{3}\)
e)\(\left(2x+\frac{1}{3}\right)^2=\frac{9}{16}\)
f) \(4^x+4^{x+3}=4160\)
g) \(\left(x-2,5\right):1\frac{1}{2}=x:2\)
h) \(\left(\frac{1}{3}+x\right):\left(x+\frac{3}{4}\right)=\frac{7}{9}\)
i) 0,81:\(\frac{x}{2}=\frac{16}{x^4}:\left(-0,9\right)\)
2. Tìm x, biết:
a)\(\left(152\frac{2}{4}-148\frac{3}{8}\right):0,2=x:0,3\)
b) \(\left[\left(6\frac{3}{5}-3\frac{3}{14}\right):2,5\right]:\left(21-1,25\right)=x:5\frac{5}{6}\)
Tìm x,y biết : |x-y|1frac{1}{2}a)frac{-1}{2}+left(x-3right):frac{-1}{2}-1frac{2}{3}c)left(frac{1}{3}-xright)^2frac{1}{4} b)2,25+frac{3}{2}:left(x-5right)2frac{1}{2}d)frac{3}{2}+frac{x-1}{3}1e)frac{-6}{8}+frac{x}{12}frac{5}{6}g)frac{1}{2}-frac{1}{3}left(x-2right)frac{-2}{3}h)frac{5}{2}left(x+1right)-frac{1}{2}3frac{1}{2}k)frac{x}{3}-frac{1}{2}-2left(x+1right)+3
Đọc tiếp
Tìm x,y biết : |x-y|=1\(\frac{1}{2}\)
a)\(\frac{-1}{2}+\left(x-3\right):\frac{-1}{2}=-1\frac{2}{3}\)
c)\(\left(\frac{1}{3}-x\right)^2=\frac{1}{4}\)
b)\(2,25+\frac{3}{2}:\left(x-5\right)=2\frac{1}{2}\)
d)\(\frac{3}{2}+\frac{x-1}{3}=1\)
e)\(\frac{-6}{8}+\frac{x}{12}=\frac{5}{6}\)
g)\(\frac{1}{2}-\frac{1}{3}\left(x-2\right)=\frac{-2}{3}\)
h)\(\frac{5}{2}\left(x+1\right)-\frac{1}{2}=3\frac{1}{2}\)
k)\(\frac{x}{3}-\frac{1}{2}=-2\left(x+1\right)+3\)
frac{4}{9}:frac{-1}{7}+6frac{5}{9}.frac{2}{3}left(frac{-1}{3}right)^4.frac{4}{11}+frac{7}{11}.left(frac{-1}{3}right)^2left(frac{-1}{7}right)^0-2frac{4}{9}:left(frac{2}{3}right)^2left(frac{1}{3}-frac{5}{6}right)^2+frac{5}{6}:2Tìm xleft(frac{3}{5}-frac{1}{2}xright)^2+812frac{7}{12}-left|frac{1}{3}-frac{1}{2}xright|frac{1}{3}frac{13}{12}-frac{1}{3}.left|frac{1}{5}-frac{1}{3}xright|frac{1}{2}Nhanh hộ mình nhaCảm ơn mn
Đọc tiếp
\(\frac{4}{9}:\frac{-1}{7}+6\frac{5}{9}.\frac{2}{3}\)
\(\left(\frac{-1}{3}\right)^4.\frac{4}{11}+\frac{7}{11}.\left(\frac{-1}{3}\right)^2\)
\(\left(\frac{-1}{7}\right)^0-2\frac{4}{9}:\left(\frac{2}{3}\right)^2\)
\(\left(\frac{1}{3}-\frac{5}{6}\right)^2+\frac{5}{6}:2\)
Tìm x
\(\left(\frac{3}{5}-\frac{1}{2}x\right)^2+8=12\)
\(\frac{7}{12}-\left|\frac{1}{3}-\frac{1}{2}x\right|=\frac{1}{3}\)
\(\frac{13}{12}-\frac{1}{3}.\left|\frac{1}{5}-\frac{1}{3}x\right|=\frac{1}{2}\)
Nhanh hộ mình nha
Cảm ơn mn