\(A=1.2.3.4...8.9-1.2.3.4...7.8-1.2.3...8.8\)
\(A=1.2.3...8.\left(9-1-8\right)\)
\(A=1.2.3...8.9.0\)
\(A=0\)
Vậy \(A=0\)
~ Học tốt ~
Tính theo cách hợp lý
a) (10^2+11^2+12^2):(13^2+14^2)
b)1.2.3....9 -1.2.3...8-1.2.3...7.8^2
c)(3.4.2^16)^2 /11.2^13.4^11-16^9
A= 1.2.3+2.3.4+3.4.5+..........+48.49.50
Tính nhanh:
9) 1 . 2 . 3 . ..... 9 - 1.2.3 . ..... 8 - 1.2.3 . .... 8\(^2\)
10) 47 . ( 23 + 50 ) - 23 . ( 47 + 50)
Tính B = 1.2.3 + 2.3.4 + ... + (n - 1)n(n + 1)
A=1.2.3+2.3.4+3.4.5+...99.100.101.Tính A. Mơn nhiều ^_^
1.2.3+2.3.4+3.4.5+..+99.100.101
p=1.2.3+2.3.4+3.4.5+...+99.100.101
Tính
B = \(\frac{3}{1.2.3}+\frac{3}{2.3.4}+...+\frac{3}{49.50.51}\)
Tính : \(\frac{1}{1.2.3}+\frac{1}{2.3.4}+\frac{1}{3.4.5}+...+\frac{1}{48.49.50}\)