ta nhóm lại với nhau
(\(\dfrac{1}{4}\)+\(\dfrac{1}{12}\))+(\(\dfrac{1}{24}\)+\(\dfrac{1}{40}\))+(\(\dfrac{1}{60}\)+\(\dfrac{1}{84}\))
=\(\dfrac{1}{3}\)+\(\dfrac{1}{15}\)+\(\dfrac{1}{35}\)
=\(\dfrac{3}{7}\)
đúng thì mình xin cái theo dõi nha bạn
1. So sanh
a) 42/43 va 58/59
b) 18/31 va 15/37
c) 53/57 va 531/571
d) 25/26 và 25251/26261
e) 3535.232323/353535.2323; 3535/3534 va 2323/2322
g) 13/38 va 1/3
2.Chung minh rang:
a) N=1/4^2+1/6^2+1/8^2+...+1/(2n)^2 < 1/4
b) 1/26+1/27+1/28+...+1/50=1-1/2+1/3-1/4+...+1/49-1/50
c) A=1/6+1/24+1/60+...+1/6840 < 1/4
d) B= 36/15+36/105+36/315+...+36/19575 < 3
Mn oi!!!!! Giup minh lam 2 bai nay voi!!!!!
1)tìm x
a)(x-7/18).18/29=-12/29
2)tính nhanh
a)0,25.2và1/3.30,05/8/45
b)(-3,3).-15/64+(0.8- "2và4/15");1và23/24
c)1 và 13/15.3.(0,5)2.3+(8/15-1và19/60):1và24/24
Bài 1 : Thực hiện phép tính ( nếu có thể )
a. 3/7 . 9/26 - 1/14 .1/13 -1/7
b. f [2/3-1/4+ 5/11 ]: [5/12 + 1 - 7/11 ]
c. -1/21 + -1 /28 - -1/21 - 3/14
d ( -1 /5 + 3/12 ) + -3/4
HELP !!
Tính B = \(\dfrac{1}{6}+\dfrac{1}{24}+\dfrac{1}{60}+.......+\dfrac{1}{990}\)
Bài 1 Tính
a) ( \(\dfrac{-2}{3}\) + \(1\dfrac{1}{4}\) - \(\dfrac{1}{6}\) ) : \(\dfrac{-24}{10}\)
b) \(\dfrac{13}{15}\) x 0.25 x 3 + ( \(\dfrac{8}{15}\) - \(1\dfrac{19}{60}\) ) \(1\dfrac{23}{24}\)
c) ( \(\dfrac{12}{32}\) + \(\dfrac{5}{-20}\) - \(\dfrac{10}{24}\) ) : \(\dfrac{2}{3}\)
d) \(4\dfrac{1}{2}\) : ( 2.5 - \(3\dfrac{3}{4}\) ) + ( -\(\dfrac{1}{2}\) )
e) \(\dfrac{-5}{2}\) : ( \(\dfrac{3}{4}\) - \(\dfrac{1}{2}\) )
thực hiện phép tính( hợp lí nếu có thể)
\(\dfrac{-5}{9}+1\dfrac{5}{9}.\left(\dfrac{3}{4}-\dfrac{2}{5}\right):7^2\)
\(1\dfrac{13}{15}.0,75-\left(\dfrac{104}{195}+25\%\right).\dfrac{24}{47}-3\dfrac{12}{13}:3\)
\(1\dfrac{13}{15}.\left(0,5\right)^2.3+\left(\dfrac{8}{15}-1\dfrac{19}{60}\right):1\dfrac{23}{24}\)
tìm x
\(60\%x+0,4x+x:3=2\)
\(-2x-\dfrac{-3}{5}:\left(0,5\right)^2=-1\dfrac{1}{4}\)
\(\left(\dfrac{2}{3}-x\right):\dfrac{3}{4}=\dfrac{1}{5}\)
tính:
a) \(\left(\dfrac{1}{2}-1\right)\cdot\left(\dfrac{1}{3}-1\right)\cdot\left(\dfrac{1}{4}-1\right)\cdot...\left(\dfrac{1}{1000}-1\right)\)
b) \(\dfrac{3}{^22}\cdot\dfrac{8}{^23}\cdot\dfrac{15}{^24}\cdot...\dfrac{99}{^210}\)
giúp mik với nhék! mik đang cần gấp.
Bài 1, Tìm x, biết
a) - x + 821 + 534 = 499 + (x - 84)
b) x - 96 = (448 - x) - 150
c) - (754 + x) = (x - 12 - 741) - 23
d) (6 + x) - (17 - 21) = -25
e) 17 - (x+2) = 3
h) -10 - (31 - x) = 40
tim x
a) 1/6x + 1/12x + 1/20x +...+1/2450x = 1
b) (2/2/9 - x) = 1/12 + 1/20 +1/30 +1/42 + 1/56 + 1/72
Help me . I need urgent