\(D=\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+..........+\dfrac{1}{256}+\dfrac{1}{512}\)
\(\Leftrightarrow2D=1+\dfrac{1}{2}+\dfrac{1}{4}+......+\dfrac{1}{256}\)
\(\Leftrightarrow2D-D=\left(1+\dfrac{1}{2}+.....+\dfrac{1}{256}\right)-\left(\dfrac{1}{2}+\dfrac{1}{4}+.....+\dfrac{1}{512}\right)\)
\(\Leftrightarrow D=1-\dfrac{1}{512}=\dfrac{511}{512}\)
\(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) +............ + \(\dfrac{1}{256}\) + \(\dfrac{1}{512}\) = ?
BT1: Tìm x, biết
3) \(x:\dfrac{1}{2}+x:\dfrac{1}{4}+x:\dfrac{1}{8}+...+x:\dfrac{1}{512}=511\)
1 x 2 x 4 x 8 x ... x 256 = ?
a, Tìm x, biết 13,44 . x - (1,6 + x) . 0,5 - 3,7 . (x - 0,9) = 13,618
b, Tính H = 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256
512 -512/2 -512/2^2 -512/2^3 -512/2^4-512/2^5-512/2^6-512/2^7-512/2^8-512/2^9-512/2^10
1,Tính
A,15/16.4/3-1/2÷5/4+3
B,(2/3-3/8)÷(3/5+1/4)
C,15/8×(1/3+1/8)-3/8÷3/4
D,20/21÷(4/5-1/10)+13/15÷5/26
x5+2x =91
4^x-3 =256
2^3x:2^x=16
(x-2)3 =125
5chia hết cho x - 1 , (x >1)
Tìm x, biết :
a, \(2(x-3)-3(x-1)=2x+6\)
b, \(2(x+7)-4(x-2)=10\)
c,\(10-(1-x)^2=6\)
d,\((x-3)^3-[(-2)^3+2^3](1+3+5+7+...+2001)=-512\)
Bài 1: Tính
a, (4/1/9+3/1/4). 2/1/4+2/3/4
b, 9/23. 5/8+ 9/23. 3/8 - 9/23
c, 1+ (9/10 - 4/5) : 3/1/6
d, (-7+/13/) - (13- / -7/ -25) - (25 +/- 10/ -9)
