=> 3S = 1.2.3 + 2.3.3 + 3.4.3 + ... + 99.100.3
= 1.2.(3 - 0) + 2.3.(4 - 1) + 3.4.(5 - 2) + ... + 99.100.(101 - 98)
= 1.2.3 - 0 + 2.3.4 - 1.2.3 + 3.4.5 - 2.3.4 + ... + 99.100.101 - 98.99.100
= 99.100.101
=> S = 99.100.101 / 3
=> S = 333300
Tinh tong S=1.2+2.3+3.4+4.5+...+99.100
tinh tong
1.2+2.3+3.4+.......+99.100
tinh tong
D=1.2+2.3+3.4+.....+99.100
tinh 1 cách thuận tiện:
Tính tổng : S=1.2+2.3+3.4+.....+99.100
tinh tong S = 1.2 + 2.3 + 3.4 + ...............+ 99. 100
1:Tim x
( x-3)(x-5)=0
(x+7).35 = 2.35
2 : Tinh tong
1.2+2.3+3.4+....................+99.100
Tinh tong: S= 1/1.2 + 1/2.3+ 1/ 3.4 ..... + 1/9.10?
tinh
1.2+2.3+3.4+....+99.100
TINH
A=1.2+2.3+ 3.4+...+99.100
