bai 1) tim x, y
x.y-x+2y=3
bai2 ) cmr
a)1/2-1/4+1/8-1/16+1/32-1/64<1/3
b) 1/3-2/3^2+3/3^3-4/3^4+....+99/3^99-100/3^100<3/16
c)1cho tổng gồm 2014 số hạng : s=1/4+2/4^2+3/4^3+.....2014/4^2014
Những câu hỏi liên quan
1. tinh nhanh: 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128
2. tim x: ( x + 1/2 ) + ( x +1/4 ) + ( x + 1/8 ) + ( x + 1/16 ) = 1
\(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\)
\(2\times A=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\)
\(2\times A-A=\left(1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\right)-\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\right)\)
\(A=1-\frac{1}{128}\)
\(A=\frac{127}{128}\)
\(B=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\)
\(2\times B=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}\)
\(B=1-\frac{1}{16}=\frac{15}{16}\)
\(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=1\)
\(\Leftrightarrow4\times x+\frac{15}{16}=1\)
\(\Leftrightarrow4\times x=\frac{1}{16}\)
\(\Leftrightarrow x=\frac{1}{64}\)
Bai 1;Tim x,y,z
a; x/z+y+1=y/x+z+1=z/x+y-2=x+y+z
b; 3x/8=3y/64=3z/216 va 2x^2+2y^2-z^2=1
[ 1/2+1/4+1/8+1/16+1/32+1/64+1/128]x X =1
\(\frac{127}{128}\times x=1\)
\(\Rightarrow x=\frac{128}{127}\)
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minh muon ban trinh bay ro rang hon
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BAI 1: TIM X BIET;
a; (x-1)5= -32
b; ( 23:4) * 2X+1=64
a)(x-1)5=(-32)=(-2)5
=>x-1=-2
x=-2+1
x=-1
b)(23/4)*2x+1=64
(8/4)*2x+1=64
2*2x+1=64
2x+1+1=26
=>x+2=6
x=6-2
x=4
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tìm x biết
1+1/2-1/4-1/8-1/16-1/32-1/64+x =45
X*[1/2+1/4+1/8+1/16+1/32+1/64+1/128]=127/128
X x (1/2+1/4+1/8+1/16+1/32+1/64+1/128) = 127/128
X x 127/128 = 127/128
X = 127/128 : 127/128
X = 1
bài 1
(4^2+1)(4^4+1)(4^8+1)(4^16+1)(4^32+1)-1/15*4^64
Bài 2:Cho x+1/x=10. Tính S=x^5+1/x^5
Bài 2:
Ta có: \(\frac{x+1}{x}=10\) hay \(\frac{x^1+1^1}{x^1}=10^1\)
Nên suy ra : \(\frac{x^5+1}{x^5}=10^5\)
= 100000 ( do 15 cũng sẽ =1 nên không viết mũ 5 cũng chả sao)
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a)234 x 4 + 234 x 5 + 234
b)135 x16 - 135 x 2 - 4 x 135
c) 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64
a,234.4+234.5+234=234(4+5+1)=234.10=2340
b,135.16-135.2-135.4=135(16-4-2)=135.10=1350
c,1/2+1/4+1/8+1/16+1/32+1/64=1-1/2+1/2-1/4+1/4-1/8+1/8-1/16+1/16-1/32=1-1/32=31/32
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a) 234 x4 + 234 x 5 + 234 = 234 x ( 1+4+5)=2340
b)135 x16 -135 x2 -4 x135 =135 x (16-2-4) =1350
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a) 234.(4+5+1)=234.10=2340
b)135.(16-2-4)=135.10=1350
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Xem thêm câu trả lời
bai 1: Tinh nhanh
a) 1/2 + 1/4 + 1/8 + 1/16 + 1/32
b) 1/2 x 1/2 + 1/2 x 1/3 + 1/3 + 1/3 + 1/4 + 1/4 x 1/5 + 1/5 x 1/6
1.a
1/2+1/4+1/8+1/16+1/32
= 1/2+1/2-1/4+1/4-1/8+1/8-1/16+1/16-1/32
= 1-1/32=31/32
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1b
\(\frac{1}{2}.\frac{1}{2}+\frac{1}{2}.\frac{1}{3} +\frac{1}{3}+\frac{1}{3}+\frac{1}{4}+\frac{1}{4}.\frac{1}{5}+\frac{1}{5}.\frac{1}{6}\)
\(=\frac{1}{4}+\frac{1}{6}+\frac{2}{3}+\frac{1}{4}+\frac{1}{20}+\frac{1}{30}\)
\(=\frac{5}{20}+\frac{5}{30}+\frac{20}{30}+\frac{5}{20}+\frac{1}{20}+\frac{1}{30}\)
\(=\left(\frac{5}{20}+\frac{5}{20}+\frac{1}{20}\right)+\left(\frac{5}{30}+\frac{20}{30}+\frac{1}{30}\right)\)
\(=\frac{11}{20}+\frac{26}{30}\)
\(=\frac{11}{20}+\frac{13}{15}\)
\(=\frac{17}{12}\)
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Đó là các cách bạn Võ Thạch Tín đã nêu ra nên mình ko còn câu trả lời nào hết
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