(-1/1/5) . (-1/1/6) . (-1/1/7) ....... (-1/1/2011
tinh ho mk cac bn nha
Cho A= 5/9 - 7/8 + 2/3 + 4/9 -1/8 +1/3
B= 1/2 + 1/6 +1/12 + 1/20 + 1/30 + 1/42
a) Tính A và B.
b) Tìm C bíêt ( A - 7B) cua C bang 2010.
Cac bn thong cam nha , dien thoai mk ko viet dau dc .Bn nao giup mk , mk se tick.
A=5/9 - 7/8 + 2/3 + 4/9 - 1/8 + 1/3
B= 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42
a) Tính A và B
b) Tìm C bíêt ( A - 7B) cua C bang 2010
Cau A và B mk dã giai roi , cau A ra 1, B ra 6/7 ,cac bn chi can giup mk cau C thoi , cauC mk ko bt cach giai!!!
Bn nao giup mk , mk se tick.
a,2/9-5/7+20/33+8/21+5/18-6/22
b, 1/2+1/3-1/4+1/6+1/8+1/16+1/32+1/64+1/128
c,5-1/2-5/6-11/12-19/20-29/30
các bn giúp mk nha
bai 1 tinh nhanh
a . 1/5x6 +1/6x7+ 1/7x8 + 1/8x9 +1/9x10
b . 1/1x2 + 1/2x3 + ....... + 1/99x100
c . 2/3x5 + 2/5x7 + 2/7x8 + 2/8x9
d . 2/3x5 + 2/5x7 + .......+ 2/98x100
bai 2 tinh hop li
9/13 + 14/6 + 1/9 + 4/6 + 7/13 + 17/19
bai 3 dien dau ( > , < , = )
a . 3/4 + 5/2 ....... 5/8 + 2 3/5 ( hon so )
B . 3 1/5 - 8/3 ......... 17/5 - 2 12/5 hon so
c . 2 4/9 + 18/7......... 22/9 + 2 4/7
giup mk nha cac ban , mai mk phai nop bai roi toi nay mk se lay y kien cua cac ban , giup mk nha
b1
a) \(\dfrac{1}{5.6}+\dfrac{1}{6.7}+\dfrac{1}{7.8}+\dfrac{1}{8.9}+\dfrac{1}{9.10}\)
\(=\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{10}\)
\(=\dfrac{1}{5}-\dfrac{1}{10}\)
\(=\dfrac{2}{10}-\dfrac{1}{10}\)
\(=\dfrac{1}{10}\)
b) \(\dfrac{1}{1.2}+\dfrac{1}{2.3}+...+\dfrac{1}{99.100}\)
\(=\dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{99}-\dfrac{1}{100}\)
\(=\dfrac{1}{1}-\dfrac{1}{100}\)
\(=\dfrac{99}{100}\)
c) \(\dfrac{2}{3.5}+\dfrac{2}{5.7}+\dfrac{2}{7.9}+\dfrac{2}{9.11}\)
\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{11}\)
\(=\dfrac{1}{3}-\dfrac{1}{11}\)
\(=\dfrac{8}{33}\)
d) \(\dfrac{2}{3.5}+\dfrac{2}{5.7}+...+\dfrac{2}{99.101}\)
\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+...+\dfrac{1}{99}-\dfrac{1}{101}\)
\(=\dfrac{1}{3}-\dfrac{1}{101}\)
\(=\dfrac{98}{303}\)
thực hiện phép tính:
a, [ 6 . ( -1/3 )2 - 3 . ( -1/3 ) + 1 ] : ( -1/3 - 1 )
b, ( -4/7 + 2/5 ) : 2/3 + ( -3/7 + 3/5 ) : 2/3
CÁC BN GIÚP MK VS NHA! MK SE TICK THAT NHIU
tim da thuc B biet:
\(B-\left(3x^6-4xy^5+\frac{1}{3}xy^2-\frac{3}{2}\right)=\left(7x^6-\frac{1}{2}xy^5-xy^2-\frac{1}{3}\right)\)
giup mk nha cac bn , ai co cach giai ro rang mk se tick 3 cai
1 + 11 + 11 + 11 + 11 + 11 + 1= 13+115
ai tick mk mk tick lai cho nha cac bn
sai vi cau nay phai bang 12 + 55
ai k mk mk k lai cho nha
Sai vì đây là phép cộng nên ko thể là ngủ đc
giúp mk nha mấy bn
1 Tính
a) 4/4.13+11/13.24+7/8.45
b) (1/10-1).(1/11-1).....(1/2017-1)
2 Tìm x
a) 5/6-(1/2+x)=1/5-2x+1/3-1/5
b) -5.(x+1/5)-1/2.(x-2/3)=3/2.x-5/6
c) 1/3.x+2/5.(x-1)=0
(x-1)^3=(x*1)^5
Cac bn ho minh nhe
Ta thay x -1 = x và x.1 = x ta có :
x3 = x5 thì x = 1
Vậy x -1 = 1 và x .1 = x. Nhưng như vậy thì (x-1)3=(x.1)5 sẽ là 03 = 15 => 0 = 1
=> x \(\in\varphi\)