3.(2 ngũ 2+1).(2^4+1).(2^8+1).(2^16+1).......(2^128+1)
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b: A=1/3+1/9+...+1/3^10
=>3A=1+1/3+...+1/3^9
=>A*2=1-1/3^10=(3^10-1)/3^10
=>A=(3^10-1)/(2*3^10)
c: C=3/2+3/8+3/32+3/128+3/512
=>4C=6+3/2+...+3/128
=>3C=6-3/512
=>C=1023/512
d: A=1/2+...+1/256
=>2A=1+1/2+...+1/128
=>A=1-1/256=255/256
a) \(5^2.3^5.\left(\frac{3}{5}\right)^2\)
\(=25.243.\frac{9}{25}\)
\(=6075.\frac{9}{25}\)
\(=2187\)
b) \(4.32.2^3.\frac{1}{16}\)
\(=4.32.8.\frac{1}{16}\)
\(=128.8.\frac{1}{16}\)
\(=1024.\frac{1}{16}\)
\(=64\)
c) \(\left(-2\frac{1}{3}\right)^2.\left(-\frac{1}{4}\right)^2\)
\(=\frac{49}{9}.\frac{1}{16}\)
\(=\frac{49}{144}\)
d) \(\frac{9^5.5^7}{45^7}\)
\(=\frac{9^5}{9^7}\)
\(=\frac{1}{9^2}=\frac{1}{81}\)
e) 103 + 5.102 + 53
= 1000 + 5.100 + 125
= 1005 . 12500
= 13505
P/s: Mũ not ngũ ^^
Câu a : Ta có :
\(B=\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\)
\(=\left(2^2-1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\)
\(=\left(2^4-1\right)\left(2^4+1\right)\left(2^8+1\right)\)
\(=\left(2^8-1\right)\left(2^8+1\right)\)
\(=2^{16}-1< 2^{16}\)
Vậy \(A>B\)
Câu b : Ta có :
\(A=4\left(3^2+1\right)\left(3^4+1\right)...\left(3^{64}+1\right)\)
\(=\dfrac{8\left(3^2+1\right)\left(3^4+1\right)...\left(3^{64}+1\right)}{2}\)
\(=\dfrac{\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)...\left(3^{64}+1\right)}{2}\)
\(=\dfrac{\left(3^4-1\right)\left(3^4+1\right)...\left(3^{64}+1\right)}{2}\)
\(=\dfrac{...\left(3^{64}-1\right)\left(3^{64}+1\right)}{2}\)
\(=\dfrac{3^{128}-1}{2}< 3^{128}-1\)
Vậy \(A< B\)
a: =>1/12*x^2=4/3
=>x^2=4/12*12=48/12=4
=>x=2 hoặc x=-2
b: =>1/5x-4/5=0 hoặc x+1/4=0
=>x=-1/4 hoặc x=4
c: =>5x+1/4=3/4 hoặc 5x+1/4=-3/4
=>5x=-1 hoặc 5x=1/2
=>x=1/10 hoặc x=-1/5
a) = \(\frac{127}{96}\)
b) = \(\frac{255}{256}\)
c) Mik bỏ nha
d) = \(\frac{1023}{512}\)
e) = \(\frac{2343}{625}\)
\(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\)
\(2\times A=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\)
\(2\times A-A=\left(1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\right)-\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\right)\)
\(A=1-\frac{1}{128}\)
\(A=\frac{127}{128}\)
\(B=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\)
\(2\times B=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}\)
\(B=1-\frac{1}{16}=\frac{15}{16}\)
\(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=1\)
\(\Leftrightarrow4\times x+\frac{15}{16}=1\)
\(\Leftrightarrow4\times x=\frac{1}{16}\)
\(\Leftrightarrow x=\frac{1}{64}\)