chứng minh rằng :1/2_1/4+1/8_1/16+1/32_1/64<1/3
Tinh gia tri moi biêu thuc sau:a.0,1+0,2+0,3+...+0,9+0,10+0,11+...+0,19. B. (1999×1998+1998×1997)×(1+1/2:1 1/2_1 1/3)
cho A=1/1-1/2+1/2_1/4+...+1/9-1/10
B=(1/1+1/2+1/3+...+1/10)-2.(1/2+1/4+...+1/10)a, so sánh Avaf B
b, chứng minh: A=1/6+1/7+1/8+1/9+1/10
Tìm số tự nhiên x, biết
a) ( x + 1 ) 2 = 16
b) ( x + 1 ) 3 = 27
c) ( x + 1 ) 3 = 16
d) ( 2 . x - 1 ) 3 = 125 .
a,1/2*x+2/3*(x-2)=1/3
b,16x-1:16=44
A =1/6 x 11 + 1/11 x 16 + 1 phần 16 x 21 + ........+ 1/496 x 501
B = 2/3 +2/15 + 2/ 35 +.....+2/19 x21
Tìm x,biết:
a)(1/2+1/4+1/6+1/8+1/16):x=3/1*2+3/2*3+3/3*4+...+3/15*16
nhanh nha,cần gấp anwser
C1:(5-|x|).(x-3)=0
C2:(x-3)+(x-2)+(x-1)+...+15+16=16
Rút gọn biểu thức:
A) x – ( x/2 + 1/2 )
B) (x/2 – 1/2) : 2 + 1/2
C) (x/2 – 1/2) – (x/4 + 1/4)
D) (x/4 – 3/4) : 2 + 1/2
E) (x/4 – 3/4) – (x/8 + 1/8)
F) (x/8 – 7/8) : 2 + 1/2
G) (x/8 – 7/8) – (x/16 + 1/16)
H) (x/16 – 15/16) : 2 + 1/2
I) (x/16 – 15/16) – (x/32 + 1/32)
a) 5/6 x 11/4 - 5/4 x 23/6
b) 9/16 x 13/4 - 9/4 x 5/16 + 9/16 x 17/
hay tinh tong:
1/1 x 2 + 1/2 x 3 + 1/3 x 4 + .... + 1/n (n + 1)
chung minh:
1/22 + 1/32 + 1/42 + ..... + 1/n2 < 1
giai dum nhe