Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
ta có :\(E=\frac{2019^{2019}+1}{2019^{2020}+1}\Leftrightarrow2019\cdot E=\frac{2019^{2020}+2019}{2019^{2020}+1}=1+\frac{2019}{2019^{2020}+1}\)
\(F=\frac{2019^{2020}+1}{2019^{2021}+1}\Leftrightarrow2019\cdot F=\frac{2019^{2021}+2019}{2019^{2021}+1}=1+\frac{2019}{2019^{2021}+1}\)
vì \(\frac{2019}{2019^{2020}+1}>\frac{2019}{2019^{2021}+1}\) nên E>F
E=2019 x 2019 x 2019 x ........ x 2019 x2019 +1 /2019 x 2019 x 2019 x.........x 2019 x 2019 + 1
E=1+1/2019+1
E=2/2020
E=1/1010
F=2019 x 2019 x 2019 x .......... x 2019 x 2019 +1 / 2019 x 2019 x 2019 x ....... x 2019 x 2019 +1
F= 1+1/2019+1
F=2/2020
F=1/1010
từ đó ta có E=F(=1/1010)
Vì a+b chia hết cho 2 mà ta lại có 2b chia hết cho 2 với mọi b thuộc N nên:
a+b+2b chia hết cho 2 hay a+3b chia hết cho 2
=>ĐPCM
1I always watch TV
I often go for a walk
I usually go swimming
I never read newspaper
I sometimes go jogging
2.I am watching TV
I am surfing the Internet
I am skiing
I am dancing
I am studying abroad
Thì hiện tại đơn :
\(1,\)My brother brushes his teeth everyday
\(2,\)My father watch television in the afternoon
\(3,\)My sister goes to the market on Sunday
\(4,\)They often play football in the evenning
\(5,\)I comb my hair every day
Thì hiện tại tiếp diễn :
\(1,\)He is watching a video
\(2,\)They are reading a book
\(3,\)She is eating lunch in the lunchroom
\(4,\)Listen ! She is playing the piano
\(5,\)Please be quiet ! The baby is sleeping .
~~ The_end ~~
Mong các bn tk ủng hộ cho mk ạ !
\(Thanks\)\(very\:\)\(much\)\(!!!!!\)
Đáng nhẽ đê như vầy:
A= 2 + 22 + 23 + 24 + ..... + 22015
=> A = (2 + 23) + ( 22 + 24 ) + ..... + ( 22012 + 22014) + (22013 + 22015)
<=> A = 2.( 1 + 4 ) + 22. ( 1 + 4) + ...... + 22012.(1 + 4) + 22013.(1 + 4)
=> A = 2.5 + 22. 5 + ...... + 22012.5 + 22013.5
=> A = 5. ( 2 + 22 + 23 + .... + 22013) chai hết cho 5