\(2^2\cdot3^2-3^5:3^2\)
\(=\left(2\cdot3\right)^2-3^{\left(5-2\right)}\)
\(=6^2-3^3\)
\(=36-27\)
`=9`
a; ( 2+2^2+2^3+........+2^60) chia hết cho 3; 7; 15
b; (1+3+3^2+3^3+......+3^1991) chia hết cho 13; 41
c; ( 3+3^2+3^3+........+3^1998) chia hết cho 12; 39
bài 3:
a) x - 3/4 = 6 x 3/8 b) 7/8 : x = 3 - 1/2 c) x + 1/2 x 1/3 = 3/4
d) 3/2 x 4/5 - x = 2/3 e) X x 3 1/3 = 3 1/3 : 4 1/4 f) 5 2/3 : x = 3 2/3 - 2 1/2
Cho D=2^3/3^3+2^3/5^3+2^3/7^3+...+2^3/2013^3
so sánh D với 2/3
Chứng minh rằng:
a,A=1/2+1/2^2+1/2^3+.+1/2^2<1
b,B=1/3+1/3^2+1/3^3+...+1/3^n<1/2
c,B=1/2-1/2^2+1/2^3-1/2^4+...+1/2^2015-1/2^2016<1/3
d,D=1/3+2/3^2+3/3^3+4/3^4+...+100/3^100<3/4
1^3 + 2^3
1^3 + 2^3 + 3^3
1^3 + 2^3 + 3^3 + 4^3
A= 2+2^2+2^3+...+2^19+2^20
b=2+2^3+2^5+...2^97+2^99
C=5+5^2+5^3+...+5^50
D=1+3+3^2+3^3+...+3^100
tinh 3/2+3/(2^2)+3/(2^3)+3/(2^4)+...3/(2^10)
So sánh:
A=(1+2+2^2+2^3+2^4)/(1+2+2^2+2^3)
B=(1+3+3^2+3^3+3^4)/(1+3+3^2+3^3)
Giải nhanh giùm mình nhé ! Ai làm nhanh, đúng mình tặng ngay 1 like !
A=1/2+2/2^2+3/2^3+...+100/2^100
B=1/3+2/3^2+3/3^2+...+100/3^100
N=(1^2+2^3+3^4+4^5).(1^3+2^3+3^3+4^3).(3^8-81^2)
