bài 4:So sánh
A= \(\dfrac{1}{1^2}+\dfrac{1}{2^2}+\dfrac{1}{3^2}+...+\dfrac{1}{50^2}vớiB=\dfrac{173}{100}\)
cho A=\(\dfrac{1}{1^2}+\dfrac{1}{2^2}+\dfrac{1}{3^2}+\dfrac{1}{4^2}+.......+\dfrac{1}{50^2}\) chứng minh A<2
giúp mình với đây là đề ôn thi hk2 chỉ là đề cương thui nha
tính H = \(\dfrac{\dfrac{1}{99}+\dfrac{2}{98}+\dfrac{3}{97}+...+\dfrac{98}{2}+\dfrac{99}{1}}{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{100}}:\dfrac{92-\dfrac{1}{9}-\dfrac{2}{10}-\dfrac{3}{11}-...-\dfrac{92}{100}}{\dfrac{1}{45}+\dfrac{1}{50}+\dfrac{1}{55}+...+\dfrac{1}{500}}\)
a. 2/3x-1/2=1/10
b. 39/7:x=13
c. (14/5x-50):2/3=51
d. (x+1/2)(2/3-2x)=0
e. 2/3x-1/2x=5/12
g. (x.44/7+3/7)11/5-3/7=-2
h. x.13/4+(-7/6)x-5/3=5/12
i.93/17:x+(-4/17):x+22/7:52/3=4/11
j. 17/2-|2x-3/4|=-7/4
k. (x+1/5)^2+17/25=26/25
l. -32/27-(3x-7/9)^3=-24/27
Cho A= 1/2^2 +1/3^2 + 1/4^2 + .... + 1/2015^2
Chứng minh A<3/4
Bài 2 tìm x ϵ z
a)-4/3/5 . 2 /4 /23 ≤ x ≤ -2/2/5 : 1/6/15
b)-4/1/3 . ( 1/2 - 1/6) ≤ x ≤ -2/3 . ( 1/3 . 1/2 .3/4)
Cho A= 1/2^2 + 1/3^2 + 1/4^2+......+ 1/2019^2 + 1/2020^2
Bài 1: Cho B=1+\(\dfrac{1}{2}\)+\(\dfrac{1}{3}\)+\(\dfrac{1}{4}+...+\dfrac{1}{2^{100}-1}\)
a) Chứng minh B<100
b) Chứng minh B>50
bài 1 : tìm x, biết:
A) X/3 - 1/2 = 1/5 B) x/5 + 1/2 = 6/10 c) x +3 /15 = 1/3 d) x -14/4 =1/4
đ) 1/2 x + 1/2 =5/2 n) -2/3 1/3 ( 2x -5 )=3/2 i) ( 3x -1) ( -1/2 x +5 ) =0 j) x-2/4 = 5+x/3
q) 3/x + 5 = 15% p) | x - 1/3 =5/6 m) 2| 1/2 x - 1/3 | - 3/2 = 1/4
z) ( 4,5 - 2 x) . ( -11/7) = 11/14 y) ( x/7 + 0,25 ) = -1/28
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