S1=2/3+4/9+8/27+16/81
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tính tổng:
S1= 2/3+4/9+8/27+16/81
S2= 3+3/2+3/22+...+3/29
Viết mỗi tập hợp sau bằng cách chỉ rõ tính chất đặc trưng cho các phần tử của nó:
A = {0; 2; 5}
B = {3; 9; 27; 81}
C = {4; 16; 36; 64; 100}
D = {9, 36, 81; 144}
E = {0; 4; 8; 12; 16}
G = {- 3; 9; - 27; 81}
K = {2/3; 3/8; 4/15; 5/24; 6/35}
H = {8; 14; 20; 26}
L = {- 2; 3; 5}
B={x\(\in\)N|x=3k; 1<=k<=4}
C={x\(\in\)N|x=4*a2; 1<=a<=5}
D={x\(\in\)N|x=9*a2;1<=a<=4}
E={x\(\in\)N|x=4k; 0<=x<=4}
G={x\(\in\)N|x=(-3)^k; 1<=k<=4}
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S=2/3+4/9 +8/27+16/81 = ?
Mẫu số chung là : 81.
\(S=\frac{2}{3}+\frac{4}{9}+\frac{8}{27}+\frac{16}{81}\)
\(S=\frac{2\times27}{3\times27}+\frac{4\times9}{9\times9}+\frac{8\times3}{27\times3}+\frac{16}{81}\)
\(S=\frac{54}{81}+\frac{36}{81}+\frac{24}{81}+\frac{16}{81}\)
\(S=\left(\frac{54}{81}+\frac{16}{81}\right)+\left(\frac{36}{81}+\frac{24}{81}\right)\)
\(S=\frac{70}{81}+\frac{60}{81}\)
\(S=\frac{130}{81}\)
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1. Tính tổng:a. 1 + 2 + 4 + 8 + 16 +…+ 512b. 1 + 3 + 9 + 27 + 81+… +7296h mik đi học ùi giúp iii
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1. Tính tổng:
a. 1 + 2 + 4 + 8 + 16 +…+ 512
b. 1 + 3 + 9 + 27 + 81+… +729
6h mik đi học ùi giúp iii
a: A=2^0+2^1+...+2^9
2A=2+2^2+...+2^10
=>A=2^10-1
b: B=1+3+3^2+...+3^6
=>3B=3+3^2+...+3^7
=>2B=3^7-1
=>\(B=\dfrac{3^7-1}{2}\)
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2^6 x 27^5 - 4^2 x 81^2
16 x 3^8 + 2^6 x 9^3
Viết mỗi tập hợp sau bằng cách nêu tính chất đặc trưng:
a) A = { 0; 1; 2; 3; 4 }
b) B = { 0; 4; 8; 12; 16 }
c) C = { -3; 9; -27; 81 }
d) D = { 9; 36; 81; 144 }
e) E = { 2; 3; 5; 7; 11 }
f) F = { 3; 6; 9; 12; 15 }
a) \(A=\left\{x\in N|0\le x\le4\right\}\)
b) \(B=\left\{x\in N|x=4k;0\le k\le4;k\in N\right\}\)
c) \(C=\left\{x\in Z|x=\left(-3\right)^k;1\le k\le4;k\in N\right\}\)
d) \(D=\left\{x\in N|x=k^2;k=3a;1\le a\le4;a\in N\right\}\)
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LŨY THỪABài 1: Tính1.frac{16^2}{4^5} 17.frac{9^3}{81^4}2.frac{4^5}{8^3} 18.frac{8^4}{4^3}3.frac{16^6}{8^3} 19.frac{8^4}{2^3}4.frac{32^3}{16^5}5.frac{32^5}{64^6}6.frac{27^5}{9^4}7.frac{9^6}{27^5}8.frac{81^5}{9^6}9.frac{27^4}{81^5}10.frac{81^5}{27^6}11.frac{25^6}{125^3}12.frac{4^7}{8^3}13.frac{8^4}{16^3}14.frac{8^5}{64^3}15.frac{16^6}{8^4}16.frac{8^8}{4^6}
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LŨY THỪA
Bài 1: Tính
\(1.\frac{16^2}{4^5}\) \(17.\frac{9^3}{81^4}\)
\(2.\frac{4^5}{8^3}\) \(18.\frac{8^4}{4^3}\)
\(3.\frac{16^6}{8^3}\) \(19.\frac{8^4}{2^3}\)
\(4.\frac{32^3}{16^5}\)
\(5.\frac{32^5}{64^6}\)
\(6.\frac{27^5}{9^4}\)
\(7.\frac{9^6}{27^5}\)
\(8.\frac{81^5}{9^6}\)
\(9.\frac{27^4}{81^5}\)
\(10.\frac{81^5}{27^6}\)
\(11.\frac{25^6}{125^3}\)
\(12.\frac{4^7}{8^3}\)
\(13.\frac{8^4}{16^3}\)
\(14.\frac{8^5}{64^3}\)
\(15.\frac{16^6}{8^4}\)
\(16.\frac{8^8}{4^6}\)
1/ Tính
a)9 mũ 3 lũy thừa 3.( 27^4 )^5 : 81^5.3
b) 2^11^2 : 16^5. (4^3. 8^2)^5
4 tk
\(a;\left(9^3\right)^3.\left(27^4\right)^5:81^5.3\)
\(=9^9.3.\left(\frac{27^4}{81}\right)^5=3^{18}.\left(\frac{3^{12}}{3^4}\right)^5=3^{18}.\left(3^8\right)^5=3^{18}.3^{40}=3^{58}\)
\(b;2^{11^2}:16^5.\left(4^3.8^2\right)^5=2^{22}:2^{20}.\left(2^6.2^6\right)^5\)
\(=2^2.\left(2^{12}\right)^5=2^2.2^{60}=2^{62}\)
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tính nhanh
a) 1/2+1/4+1/8+1/16+1/32
b) 1/3+1/9+1/27+1/81+1/243+1/729
A = \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\) + \(\dfrac{1}{32}\)
2 \(\times\) A = 1 + \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\)
2 \(\times\) A - A = 1 + \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\) - (\(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\) + \(\dfrac{1}{32}\))
A = 1 + \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\) - \(\dfrac{1}{2}\) - \(\dfrac{1}{4}\) - \(\dfrac{1}{8}\) - \(\dfrac{1}{16}\) - \(\dfrac{1}{32}\)
A = 1 - \(\dfrac{1}{32}\)
A = \(\dfrac{31}{32}\)
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B = \(\dfrac{1}{3}\) + \(\dfrac{1}{9}\) + \(\dfrac{1}{27}\) + \(\dfrac{1}{81}\) + \(\dfrac{1}{243}\) + \(\dfrac{1}{729}\)
3 \(\times\)B = 1 + \(\dfrac{1}{3}\) + \(\dfrac{1}{9}\) + \(\dfrac{1}{27}\) + \(\dfrac{1}{81}\) + \(\dfrac{1}{243}\)
3 \(\times\) B - B = 1 + \(\dfrac{1}{3}\) + \(\dfrac{1}{9}\) + \(\dfrac{1}{27}\) + \(\dfrac{1}{81}\) + \(\dfrac{1}{243}\) -(\(\dfrac{1}{3}\)+\(\dfrac{1}{9}\)+\(\dfrac{1}{27}\)+...+\(\dfrac{1}{729}\))
2B = 1 + \(\dfrac{1}{3}\) + \(\dfrac{1}{9}\) + \(\dfrac{1}{27}\) + \(\dfrac{1}{81}\) + \(\dfrac{1}{243}\) - \(\dfrac{1}{3}\) - \(\dfrac{1}{9}\)-\(\dfrac{1}{27}\)-...- \(\dfrac{1}{729}\)
2B = 1 - \(\dfrac{1}{729}\)
2B = \(\dfrac{728}{729}\)
B = \(\dfrac{728}{729}\) : 2
B = \(\dfrac{364}{729}\)
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