2B = 2 + 1 + 1/2 + 1/2^2 + ... + 1/2^249
2B - B = (2 + 1 + 1/2 + 1/2^2 + ... + 1/2^249) - (1 + 1/2 + 1/2^2 + 1/2^3 + ... + 1/2^250)
B = 2 - 1/2^250
Rút gọn:B=2^100-2^99+2^98-2^97+....+2^2
rút gọn biểu thức:1/2+1/2^2+1/2^3+....+1/2^100
Cho bt A=[(a-1)^2/3a+(a-1)^2-1-2a^2+4a/a^3-1+1/a-1]:2/a^2+1 Rút gọn A
Rút gọn biểu thức sau A =
3/1^2.2^2+5/2^2.3^2+7/3^2.4^2+...+(n+1)^2-1^2/n^2(n+1)^2
Bài 1 :Rút gọn A=2^100-2^99+2^97+...+2^2 -2
B=3^100-3^99+3^98-3^97+...+3^@ +1
bài 2:
Cho C =1/3+1/3^2+1/3^3+...=1/3^99
CMR C<1/2
Rút gọn:
1)3(x+1)-2|x+3|
2)2|x+3|-|4x-1|
Rút gọn A= (1/2+ 1/3+ 1/4+.....+ 1/2013)/ ( 2012+ 2012/2 + 2011/ 3+....+ 1/ 2013)
Rút gọn A= (1/2+1/3+1/4+...+1/2013)/(2012+2012/2+2011/3+...+1/2013)
rút gọn biểu thức P= 1/2-1/2*(x:1/6-1/4)-2|3x-2| khi.:
a, x>= 2/3.
b, x< 2/3
