Chương I : Số hữu tỉ. Số thực
Các câu hỏi tương tự
Tìm x,y: (5x+1)^2=36/49=(2y-1)^3
(x-2/9)^3=(2/3)^6=(y/3)^2
(8x-1)^2y+1=5^2y+1 (với y thuộc N)
1) A = \(\left(-\dfrac{25}{27}-\dfrac{31}{42}\right)-\left(\dfrac{-7}{27}-\dfrac{3}{42}\right)\)
2) B = \(\dfrac{10\dfrac{3}{10}-\left(9,5-0,25\times18\right)\div0,5}{1\dfrac{1}{5}-1\dfrac{1}{2}}\)
3) C = \(\dfrac{3}{49}\times\dfrac{19}{2}-\dfrac{3}{49}\times\dfrac{5}{2}-\left(\dfrac{1}{20}-\dfrac{1}{4}\right)^2\times\left(\dfrac{-1}{2}-\dfrac{193}{14}\right)\)
Cho B=1/2^2+1/3^2+...+1/50^2 c/m B<3/4
tính hợp lýa, A dfrac{1-dfrac{1}{sqrt{49}}+dfrac{1}{49}-dfrac{1}{left(7sqrt{7}right)^2}}{dfrac{sqrt{64}}{2}-dfrac{4}{7}+left(dfrac{2}{7}right)^2-dfrac{4}{343}}b, M 1 - dfrac{5}{sqrt{196}} - dfrac{5}{left(2sqrt{21}right)^2} - dfrac{sqrt{25}}{204} - dfrac{left(sqrt{5}right)^2}{374}
Đọc tiếp
tính hợp lý
a, A = \(\dfrac{1-\dfrac{1}{\sqrt{49}}+\dfrac{1}{49}-\dfrac{1}{\left(7\sqrt{7}\right)^2}}{\dfrac{\sqrt{64}}{2}-\dfrac{4}{7}+\left(\dfrac{2}{7}\right)^2-\dfrac{4}{343}}\)
b, M = 1 - \(\dfrac{5}{\sqrt{196}}\) - \(\dfrac{5}{\left(2\sqrt{21}\right)^2}\) - \(\dfrac{\sqrt{25}}{204}\) - \(\dfrac{\left(\sqrt{5}\right)^2}{374}\)
\(A=\dfrac{1-\dfrac{1}{\sqrt{49}}+\dfrac{1}{49}-\dfrac{1}{\left(7\sqrt{7}\right)^2}}{\dfrac{\sqrt{64}}{2}-\dfrac{4}{7}+\left(\dfrac{2}{7}\right)^2-\dfrac{4}{343}}\)
Cho biểu thức
\(M=\dfrac{1}{5}+\left(\dfrac{1}{5}\right)^2+\left(\dfrac{1}{5}\right)^3+...+\left(\dfrac{1}{5}\right)^{49}+\left(\dfrac{1}{5}\right)^{50}\)
Chứng minh rằng \(M< \dfrac{1}{4}\)
a, left(18dfrac{1}{3}:sqrt{225}+8dfrac{2}{3}.sqrt{dfrac{49}{4}}right): left[left(12dfrac{1}{3}+8dfrac{6}{7}right)-dfrac{left(sqrt{7}right)^2}{left(3sqrt{2}right)^2}right]: dfrac{1704}{445}b, dfrac{1}{1.2}+dfrac{1}{2.3}+...+dfrac{1}{99.100}c, left(1-dfrac{1}{2}right)xleft(1-dfrac{1}{3}right)x.....xleft(1-dfrac{1}{n+1}right) (n ϵ N)d, -66 x left(dfrac{1}{2}-dfrac{1}{3}+dfrac{1}{11}right) + 124 x -37 + 63 x -124e, dfrac{7}{4} x left(dfrac{33}{12}+dfrac{3333}{2020}+dfrac{333333}{303030}+dfrac{33333...
Đọc tiếp
a, \(\left(18\dfrac{1}{3}:\sqrt{225}+8\dfrac{2}{3}.\sqrt{\dfrac{49}{4}}\right)\): \(\left[\left(12\dfrac{1}{3}+8\dfrac{6}{7}\right)-\dfrac{\left(\sqrt{7}\right)^2}{\left(3\sqrt{2}\right)^2}\right]\): \(\dfrac{1704}{445}\)
b, \(\dfrac{1}{1.2}\)+\(\dfrac{1}{2.3}\)+...+\(\dfrac{1}{99.100}\)
c, \(\left(1-\dfrac{1}{2}\right)\)x\(\left(1-\dfrac{1}{3}\right)\)x.....x\(\left(1-\dfrac{1}{n+1}\right)\) (n ϵ N)
d, -66 x \(\left(\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{11}\right)\) + 124 x -37 + 63 x -124
e, \(\dfrac{7}{4}\) x \(\left(\dfrac{33}{12}+\dfrac{3333}{2020}+\dfrac{333333}{303030}+\dfrac{33333333}{42424242}\right)\)
Bài 1 : Rút gọn biểu thức sau :
1, M / x-1 / + x+2
2, N x-3 + /x-3/
3, P 22 - 1 - / x-2 /
Bài 2 : Cho :
A 1-dfrac{1}{2}+dfrac{1}{3}-dfrac{1}{4}+dfrac{1}{5}-dfrac{1}{6}+...+dfrac{1}{49}-dfrac{1}{50}
Chứng minh rằng A dfrac{5}{6}
dấu / biểu diễn giá trị tuyệt đối nhé xin lỗi tớ ko biết viết dấu giá trị tuyệt đối
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Đọc tiếp
Bài 1 : Rút gọn biểu thức sau :
1, M = / x-1 / + x+2
2, N = x-3 + /x-3/
3, P = 22 - 1 - / x-2 /
Bài 2 : Cho :
A = \(1-\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{5}-\dfrac{1}{6}+...+\dfrac{1}{49}-\dfrac{1}{50}\)
Chứng minh rằng A < \(\dfrac{5}{6}\)
dấu / biểu diễn giá trị tuyệt đối nhé xin lỗi tớ ko biết viết dấu giá trị tuyệt đối
HELP ME ~ MAI MIK PHẢI NỘP RỒI ~ 
Cho \(A=1+\dfrac{1}{2}+\dfrac{1}{3}+...+\dfrac{1}{2^{100}-1}\).
CMR: 50 <A < 100.