Toán tính a A = 1 . 2 + 2 . 3 + 3 . 4 + …. + 99 . 100 14/11/2021 By Rylee tính a A = 1 . 2 + 2 . 3 + 3 . 4 + …. + 99 . 100
A = 1 . 2 + 2 . 3 + 3 . 4 + …. + 99 . 100 <=>3A=1.2.3+2.3.(4-1)+…….+99.100.(101-98) <=>3A=1.2.3+2.3.4-1.2.3+….+99.100.101-98.99.`100 <=>3A=99.100.101=999900 <=>A=999900:3=333300 Vậy A=333300 Trả lời
A = 1 . 2 + 2 . 3 + 3 . 4 + …. + 99 . 100
<=>3A=1.2.3+2.3.(4-1)+…….+99.100.(101-98)
<=>3A=1.2.3+2.3.4-1.2.3+….+99.100.101-98.99.`100
<=>3A=99.100.101=999900
<=>A=999900:3=333300
Vậy A=333300
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