xét n=1:

=>1!=1 không chia hết cho 6

xét n=2=>1!+2!=3 không chia hết cho 6

xét n=3:

=>1!+2!+3!=9 không chia hết cho 6

xét n>3:

=>1!+2!+(3!+...+n!)=3+6k không chia hết cho 6

=>không có n

t viết dạng thui nha đề k giống đâu

1.Nêu ý nghĩa của CTHH CaSO₃

2.Lập PTHH

Nêu ý nghĩa

3.Cho các biểu diễn

Biểu diễn nào ý chỉ

a) Nguyên tử

b) Phân tử

c) CTHH

4.a) Tìm hóa trị của N trong N₂O₅; NO₂

b)Lập CTHH

5.Đốt cháy hoàn toàn 12,4 g P trong bình đựng khí oxi thu được 28,4 g P₂O₅

a) Lập PTHH của phản ứng

b) Viết công thức khối lượng

c) Tính khối lượng oxi đã phản ứng

P/s: ns chung m cứ ôn trong đề cương đi

h thì đề sinh của mk đâu

vô ib riêng vs t

\(\frac{-111}{100}\)

Đang thi vòng mấy vậy ? mấy điểm

I think in the future, most people will travel by flying cars.I think that it will have 2 wings so that it can fly as a plane. It will not be as big as the plane, but its speed will be higher than any other vehicles now.I think flying cars will use solar power with super thin batteries and they will use the technology called Vehicle-to-Vehicle communication, or V2V, which means cars will communicate with each other to avoid crashing. A flying car will be used for air transport, but it can also be used on the road. People can control it by touching on the control panel or they can set it in the automated control system. It can be used both in the city and in the countryside.I think flying cars will be one of the most popular means of transport in the future because they are environmentally friendly and we can avoid traffic jams by using them. However, I think we may need a sky safety system to avoid crashing.I think flying cars will be one of the most popular means of transport in the future because they are environmentally friendly and we can avoid traffic jams by using them. However, I think we may need a sky safety system to avoid crashing.