CMR: ( 7/65 +1) . (7/84 +1) . (7/105 +1) . (7/124 +1) ... (7/513 +1) . (7/560 +1)
Những câu hỏi liên quan
chứng minh rằng (7/65+1).(7/84+1).(7/124+1) ... (7/513+1).(7/560+1)<2
chứng minh rằng (7/65+1).(7/84+1).(7/128). ... .(7/513+1).(7/560+1)<2
bài này có vẻ khó,mình suy nghĩ đã
Bài 1:a, Cho Sfrac{1}{2^2}+frac{1}{3^2}+frac{1}{4^2}+...+frac{1}{9^2} .Chứng minh rằng frac{2}{5} S frac{8}{9}b, Tìm x thuộc z để phân số frac{x^2-5x-1}{x+2}có giá trị là số nguyênc, Chứng minh rằng left(frac{7}{65}+1right)left(frac{7}{84}+1right)left(frac{7}{105}+1right)left(frac{7}{124}+1right)...left(frac{7}{153+1}right)left(frac{7}{560}+1right) 2d, Chứng minh rằng frac{1}{3}-frac{2}{3^2}+frac{3}{3^3}-frac{4}{3^4}+frac{5}{3^5}-...+frac{99}{3^{99}}-frac{100}{3^{100}} frac{3}{16}
Đọc tiếp
Bài 1:
a, Cho S=\(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{9^2}\) .Chứng minh rằng \(\frac{2}{5}< S< \frac{8}{9}\)
b, Tìm x thuộc z để phân số \(\frac{x^2-5x-1}{x+2}\)có giá trị là số nguyên
c, Chứng minh rằng \(\left(\frac{7}{65}+1\right)\left(\frac{7}{84}+1\right)\left(\frac{7}{105}+1\right)\left(\frac{7}{124}+1\right)...\left(\frac{7}{153+1}\right)\left(\frac{7}{560}+1\right)< 2\)
d, Chứng minh rằng \(\frac{1}{3}-\frac{2}{3^2}+\frac{3}{3^3}-\frac{4}{3^4}+\frac{5}{3^5}-...+\frac{99}{3^{99}}-\frac{100}{3^{100}}< \frac{3}{16}\)
Thuc hien phep tinh:
a.3/7.11/15+3/7:15/14+2/7
b.(-7/15).5/8.15/-7(-32)
c.[(1/9:8/27):-1/3]:81/128
d.-66(1/2-1/3+1/11)+124(-37)+63(-124)
1. 80 - 4 . 5^2 + 3 . 2^3
2. 25 . 124 - 24 . 25 + 212
3 . 117 : {[79 - 3(3^3 - 17)] : 7 + 2}
4. 35 . 48 + 65 . 68 + 20 . 35
5. 2^7 : 2^3 + 2^3 . 2^0 - 1^10
6. 3978 : [359 - (2^7 : 2^4 + 39 . 8]
7. 20 - [30 - (5-1)^2]
8.
80 - 4 . 52 + 3 .23=80 - 4 . 25 + 3 . 8=80 - 100 +24=-20+24=4
25 . 124 - 24 . 25 +212=24 .(124 - 25)+212=24 . 99 +212=2376 +212=2588
35 . 48 + 65 . 68 + 20 . 35=35 . (48 +20)+65 . 68=35 . 68 +65 . 68=68 . (35 + 65)=68 . 100=6800
27 :23+23.20-110=24+23- 1=16 + 8 -1=23
câu 3,câu 6,câu 7 mk ko làm đc vì ko biết cách viết dấu móc vuông với dấu móc kép nha bạn.:) ^_^
HOK TỐT
1+2+4+5+6+7+3+5+7+5+5+2+23+65+65+7+7+7+7+7=?
1+2+4+5+6+7+3+5+7+5+5+2+23+65+65+7+7+7+7+7=240
~~~hok tốt~~~
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CMR (1/7^2)+(1/7^4)+...+(1/7^ 4n-2)-(1/7^4n)+...+(1/7^98)+(1/7^100) < 1/50
bang gi ong cung chiu vi ong hoc lop 5
D = ( 1/4 + 1/24 + 1/124) : ( 3/4 + 3/24 + 3/124) + ( 2/7 + 2/17 + 2/127) : (3/7 + 3/17 + 3/127)
\(D=\left(\dfrac{1}{4}+\dfrac{1}{24}+\dfrac{1}{124}\right):\left(\dfrac{3}{4}+\dfrac{3}{24}+\dfrac{3}{124}\right)+\left(\dfrac{2}{7}+\dfrac{2}{17}+\dfrac{2}{127}\right):\left(\dfrac{3}{7}+\dfrac{3}{17}+\dfrac{3}{127}\right)\)
\(D=\left(\dfrac{1}{4}+\dfrac{1}{24}+\dfrac{1}{124}\right):3\left(\dfrac{1}{4}+\dfrac{1}{24}+\dfrac{1}{124}\right):3\left(\dfrac{1}{7}+\dfrac{1}{27}+\dfrac{1}{127}\right):3\left(\dfrac{1}{7}+\dfrac{1}{27}+\dfrac{1}{127}\right)\)
\(D=\dfrac{1}{3}+\dfrac{2}{3}\)
\(D=1\)
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D = \(\dfrac{\dfrac{1}{4}+\dfrac{1}{24}+\dfrac{1}{124}}{\dfrac{3}{4}+\dfrac{3}{24}+\dfrac{3}{124}}\) + \(\dfrac{\dfrac{2}{7}+\dfrac{2}{17}+\dfrac{2}{127}}{\dfrac{3}{7}+\dfrac{3}{17}+\dfrac{3}{127}}\)
D = \(\dfrac{\dfrac{1}{4}+\dfrac{1}{24}+\dfrac{1}{124}}{3.\left(\dfrac{1}{4}+\dfrac{1}{24}+\dfrac{1}{124}\right)}\) + \(\dfrac{2.\left(\dfrac{1}{7}+\dfrac{1}{17}+\dfrac{1}{127}\right)}{3.\left(\dfrac{1}{7}+\dfrac{1}{17}+\dfrac{1}{127}\right)}\)
D = \(\dfrac{1}{3}\) + \(\dfrac{2}{3}\)
D = \(\dfrac{3}{3}\)
D = 1
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CMR: 1/7^2-1/7^4+1/7^6-...+1/7^98-1/7^100 < 1/50