Toán Lớp 6: cho mình hỏi với
a)E=2+2^2+2^3+2^4+…+2^100 b)F=1+3^1+3^2+3^3…3^100
g)G=5+5^3+5^5+5^7+…5^99 h) (1+2+3+…+100).(65.111-13.15.37)
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Toán Lớp 6: cho mình hỏi với
a)E=2+2^2+2^3+2^4+…+2^100 b)F=1+3^1+3^2+3^3…3^100
g)G=5+5^3+5^5+5^7+…5^99 h) (1+2+3+…+100).(65.111-13.15.37)
Comments ( 2 )
2E=2^2+2^3+2^4+2^5+………………….+2^101
2E-E=(2^2+2^3+2^4+2^5+………………….+2^101)-(2+2^2+2^3+2^4+………………….+2^100)
E=2^101-2
b) F=1+3^1+3^2+3^3+…………………………..+3^100
3F=3^1+3^2+3^3+3^4+…………………………+3^101
3F-F=(3^1+3^2+3^3+3^4+…………………………+3^101)-(1+3^1+3^2+3^3+…………………………..+3^100)
2F=3^101-1
F=(3^101-1)/2
g) G=5+5^3+5^5+5^7+………………+5^99
5^2G=5^3+5^5+5^7+5^9+…………………….+5^101
25G-G=(5^3+5^5+5^7+5^9+…………………….+5^101)-(5+5^3+5^5+5^7+………………+5^99)
24G=5^101-5
G=(5^101-5)/24
h)(1+2+3+…………………..+100).(1^2+2^2+3^2+…………………….+100^2).(65.111-13.15.37)
=(1+2+3+……………………+100).(1^2+2^2+3^2+…………………….+100^2).(7215-7215)
=A.B.0
=0