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`#3107.101107`
1.
`a,`
\(A=1+3+3^2+3^3+...+3^{2012}\)
`3A = 3 + 3^2 + 3^3 + ... + 3^2013`
`3A - A = (3 + 3^2 + 3^3 + ... + 3^2013) - (1 + 3 + 3^2 + 3^3 + ... + 3^2012)`
`2A = 3 + 3^2 + 3^3 + ... + 3^2013 - 1 - 3 - 3^2 - 3^3 - ... - 3^2012`
`2A = 3^2013 - 1`
`=> A = (3^2013 - 1)/2`
Vậy, `A = (3^2013 - 1)/2`
`b,`
\(B=1+10+10^2+10^3+...+10^{2023}\)
`10B = 10 + 10^2 + 10^3 + ... + 10^2024`
`10 B - B = (10 + 10^2 + 10^3 + ... + 10^2024) - (1 - 10 + 10^2 + 10^3 + ... + 10^2023)`
`9B = 10 + 10^2 + 10^3 + ... + 10^2024 - 1 - 10^2 - 10^3 - ... - 10^2023`
`9B = 10^2024 - 1`
`=> B = (10^2024 - 1)/9`
Vậy, `B = (10^2024 - 1)/9.`
`a)A=1+3+3^2+3^3+...+3^2012`
`=>3A=3+3^2+3^3+...+3^2013`
`=>3A-A=2A=3^2013-1`
`=>A=(3^2013-1)/2`
`b)B=1+10+10^2+...+10^2024`
`=>10B=10+10^2+10^3+....+10^2025`
`=>10B-B=9B=10^2025-10`
`=>B=(10^2025-10)/9`
\(2^3\cdot2^2\cdot2^x\cdot x^5\cdot=2^{5+x}\cdot x^5\)
\(10^2\cdot2^{10}\cdot10^3\cdot10^5=10^{10}\cdot2^{10}=2^{10}\cdot5^{10}\cdot2^{10}=4^{10}\cdot5^{10}=20^{10}\)
\(a^3\cdot a^2\cdot a^5=a^{3+2+5}=a^{10}\)
P/s: Mình chỉ hiểu ý bạn như này!
I don't now
or no I don't
..................
sorry
a,\(2^4\cdot3^5:6^4\)
\(=\frac{2^4\cdot3^6}{\left(2\cdot3\right)^4}\)
\(=\frac{2^4\cdot3^6}{2^4\cdot3^4}\)
\(=3^2\)
Bài 2
\(a,5^3\cdot8=5^3\cdot2^3=10^3=1000\)
\(b,2^5-2019^0=32-1=31\)
\(c,3^3+2^5-1^{10}=27+32-1=58\).
\(d,9^2\cdot33-81\cdot23+5^2=81\cdot33-81\cdot23+25\)
\(=81\cdot\left(33-23\right)+25\)
\(=810+25=835\)
\(g,\left[2^2+6^2\right]:5+11^2\)
\(=\left[4+36\right]:5+121\)
\(=40:5+121=8+121\)
\(=129\)
\(d,\frac{14\cdot3^{10}-5\cdot3^{10}}{3^{12}}\)
\(=\frac{3^{10}\cdot\left(14-5\right)}{3^{12}}\)
\(=\frac{3^{10}\cdot9}{3^{12}}\)
\(=\frac{3^{10}\cdot3^2}{3^{12}}=\frac{3^{12}}{3^{12}}\)
\(=1\)
a) \(4^3\cdot32^4\)
\(=\left(2^2\right)^3\cdot\left(2^5\right)^4\)
\(=2^6\cdot2^{20}\)
\(=2^{26}\)
b) \(3^{20}\cdot9^{10}\cdot27^2\)
\(=3^{20}\cdot\left(3^2\right)^{10}\cdot\left(3^3\right)^2\)
\(=3^{20}\cdot3^{20}\cdot3^6\)
\(=3^{46}\)
c) \(3^{10}\cdot7^{10}\)
\(=\left(3\cdot7\right)^{10}\)
\(=21^{10}\)
d) \(6^{15}:6^{14}\)
\(=6^{15-14}\)
\(=6\)
e) \(28^3:7^3\)
\(=4^3\cdot7^3:7^3\)
\(=4^3\)
\(=2^6\)
các bạn có thể giải chi tiết cho mình được ko . Mình cần ghấp lắm
Lời giải:
$A=10^0+10^1+10^2+....+10^{12345678}$
$10A=10^1+10^2+10^3+....+10^{12345679}$
$10A-A=(10^1+10^2+10^3+....+10^{12345679})-(10^0+10^1+10^2+....+10^{12345678})$
$9A=10^{12345679}-10^0$
$A=\frac{10^{12345679}-1}{9}$