Tính A=22019-(22018+22017+..........+21+20)
M=22020-(22019+22018+...+21+20)
\(M=2^{2020}-2^{2020}+1=1\)
M=22020-(22019+22018+...+21+20)
\(M=2^{2020}-2^{2020}+1=1\)
Cho A=1+2+22+23+ ... +22018 , B=22019. Tính B - A
Ai làm đúng cho tick
\(A=1+2+2^2+...+2^{2018}\)
\(2A=2+2^3+2^4+...+2^{2019}\)
\(A=2A-A=1-2^{2019}\)
\(B-A=2^{2019}-\left(1-2^{2019}\right)\)
\(B-A=2^{2019}-1+2^{2019}\)
\(B-A=1\)
`#3107`
\(A=1+2+2^2+2^3+...+2^{2018}\) và \(B=2^{2019}\)
Ta có:
\(A=1+2+2^2+2^3+...+2^{2018}\)
\(2A=2+2^2+2^3+...+2^{2019}\)
\(2A-A=\left(2+2^2+2^3+...+2^{2019}\right)-\left(1+2+2^2+2^3+...+2^{2018}\right)\)
\(A=2+2^2+2^3+...+2^{2019}-1-2-2^2-2^3-...-2^{2018}\)
\(A=2^{2019}-1\)
Vậy, \(A=2^{2019}-1\)
Ta có:
\(B-A=2^{2019}-2^{2019}+1=1\)
Vậy, `B - A = 1.`
A = 1 + 2 + 22 + 23 + ... + 22018
2.A = 2 + 22 + 23 + 24 + ... + 22019
A = 22019 - 1
B - A = 22019 - (22019 - 1) = 1
22018-22017
22018-22017
Giải:
Ta có: 22018 = 22017 . 2
=> 22018 - 22017 = 22017 . 2 - 22017 = 2
B = 22018 - 22017 - 22016 - 22015 - 22014
\(B=2^{2018}-2^{2017}-2^{2016}-2^{2015}-2^{2014}\)
\(=>2B=2^{2019}-2^{2018}-2^{2017}-2^{2016}-2^{2015}\)
\(=>2B+B=2^{2019}-2^{2014}\)
\(=>B=\dfrac{2^{2019}-2^{2014}}{3}\)
21+ 22 + 23+... +22017
`@` Đặt `A=2^1+2^2+2^3+...+2^2017`
`=>2A=2(2^1+2^2+2^3+...+2^2017)`
`=>2A=2^2+2^3+...+2^2018`
`=>2A-A=(2^2+2^3+...+2^2018)-(2^1+2^2+...+2^2017)`
`=>A=2^2018-2`
Tính giá trị biểu thức (Thu gọn các tổng sau):
A = 2 + 22 + 23 + … + 22017
Ta có:
A = 2 + 22 + 23 + … + 22017
2A = 2.( 2 + 22 + 23 + … + 22017)
2A = 22 + 23 + 24 + … + 22018
2A – A = (22 + 23 + 24 + … + 22018) – (2 + 22 + 23 + … + 22017)
Vậy A = 22018 – 2
Tính giá trị biểu thức (Thu gọn các tổng sau):
A = 2 + 22 + 23 + … + 22017
Ta có: A = 2 + 22 + 23 + … + 22017
2A = 2.( 2 + 22 + 23 + … + 22017)
2A = 22 + 23 + 24 + … + 22018
2A – A = (22 + 23 + 24 + … + 22018) – (2 + 22 + 23 + … + 22017)
A = 22018 – 2
Vậy A = 22018 – 2
Tính l i m x → 2 1009 x - 2 1009 x 2 - 2 2018
A. 2 - 1010
B. 2 1009
C. 2 1010
D. 2 - 1009
Cho l i m x → ∞ f x = 2 2018 . Tính l i m x → ∞ f x - 1 f x + 1 .
A. 2 2018 - 1
B. 4 2018 + 1
C. 4 2018 - 1
D. 2 2018 + 1