Tìm kết quả sau: 4 + 22 + 23 + ....... + 2n = 22023
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a) \(A=2\left(1+2+2^2+...+2^{2022}+2^{2023}\right)⋮2\left(đpcm\right)\)
b) \(A=2\left(1+2\right)+2^3\left(1+2\right)+...+2^{2023}\left(1+2\right)\)
\(=2.3+2^3.3+...+2^{2023}.3\)
\(=3\left(2+2^3+...+2^{2023}\right)⋮3\left(đpcm\right)\)
A) A=2+22+23+...+22023+22024
A=2(1+2+22+...+22022+22023)⋮2
B) A=2+22+23+...+22023+22024
A=(2+22)+...+(22023+22024)
A=2(1+2)+...+22023(1+2)
A=2.3+...+22023.3
A=3(2+...+22023)⋮3
a: \(A=1+2+2^2+...+2^{2023}\)
=>\(2A=2+2^2+2^3+...+2^{2024}\)
=>\(2A-A=2^{2024}+2^{2023}+...+2^2+2-2^{2023}-2^{2022}-...-2^2-2-1\)
=>\(A=2^{2024}-1\)
b: \(A=\left(1+2\right)+2^2+2^3+...+2^{2023}\)
\(=3+2^2\left(1+2\right)+...+2^{2022}\left(1+2\right)\)
\(=3\left(1+2^2+...+2^{2022}\right)⋮3\)
a) A = 2⁰ + 2¹ + 2² + 2³ + ... + 2²⁰²²
2A = 2 + 2² + 2³ + 2⁴ + ... + 2²⁰²³
A = 2A - A
= (2 + 2² + 2³ + 2⁴ + ... + 2²⁰²³) - (2⁰ + 2¹ + 2² + 2³ + ... + 2²⁰²²)
= 2²⁰²³ - 2⁰
= 2²⁰²³ - 1
Vậy A = B
b) A = 2021 . 2023
= (2022 - 1).(2022 + 1)
= 2022.(2022 + 1) - 2022 - 1
= 2022² + 2022 - 2022 - 1
= 2022² - 1 < 2022²
Vậy A < B
Ta có \(A=\dfrac{1}{2}+\dfrac{2}{2^2}+\dfrac{3}{2^3}+...+\dfrac{2022}{2^{2022}}+\dfrac{2023}{2^{2023}}\)
\(2A=1+\dfrac{2}{2}+\dfrac{3}{2^2}+...+\dfrac{2022}{2^{2021}}+\dfrac{2023}{2^{2022}}\)
\(2A-A=\left(1+\dfrac{2}{2}+\dfrac{3}{2^2}+...+\dfrac{2022}{2^{2021}}+\dfrac{2023}{2^{2022}}\right)-\left(\dfrac{1}{2}+\dfrac{2}{2^2}+\dfrac{3}{2^3}+...+\dfrac{2022}{2^{2022}}+\dfrac{2023}{2^{2023}}\right)\)\(A=1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{2021}}+\dfrac{1}{2^{2022}}\) - \(\dfrac{2023}{2^{2023}}\)
Đặt B = \(1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{2021}}+\dfrac{1}{2^{2022}}\)
2B = \(2+1+\dfrac{1}{2}+...+\dfrac{1}{2^{2020}}+\dfrac{1}{2^{2021}}\)
2B - B = \(\left(2+1+\dfrac{1}{2}+...+\dfrac{1}{2^{2020}}+\dfrac{1}{2^{2021}}\right)-\left(1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{2021}}+\dfrac{1}{2^{2022}}\right)\)B = 2 - \(\dfrac{1}{2^{2022}}\)
Suy ra A = 2 - \(\dfrac{1}{2^{2022}}\) - \(\dfrac{2023}{2^{2023}}\) < 2
Vậy A < 2
\(A=\dfrac{1}{2}+\dfrac{2}{2^{2}}+\dfrac{3}{2^{3}}+...+\dfrac{2022}{2^{2022}}+\dfrac{2023}{2^{2023}}\)
\(2A=1+\dfrac22+\dfrac3{2^2}\ +\,.\!.\!.+\ \dfrac{2022}{2^{2021}}+\dfrac{2023}{2^{2022}}\\2A-A=\left(1+\dfrac22+\dfrac3{2^2}\ +\,.\!.\!.+\ \dfrac{2022}{2^{2021}}+\dfrac{2023}{2^{2022}}\right)-\left(\dfrac12+\dfrac2{2^2}+\dfrac3{2^3}\ +\,.\!.\!.+\ \dfrac{2022}{2^{2022}}+\dfrac{2023}{2^{2023}}\right)\\A=1+\dfrac12+\dfrac1{2^3}\ +\,.\!.\!.+\ \dfrac1{2^{2021}}+\dfrac1{2^{2022}}-\dfrac{2023}{2^{2023}}\\2\left(A+\dfrac{2023}{2^{2023}}\right)=2+1+\dfrac12+\dfrac1{2^2}\ +\,.\!.\!.+\ \dfrac1{2^{2020}}+\dfrac1{2^{2021}}\\A+\dfrac{2023}{2^{2023}}=2-\dfrac1{2^{2022}}\\A=2-\dfrac1{2^{2022}}+\dfrac{2023}{2^{2023}}<2\)
Bài 1
a) S = 1 + 2 + 2² + 2³ + ... + 2²⁰²³
2S = 2 + 2² + 2³ + 2⁴ + ... + 2²⁰²⁴
S = 2S - S = (2 + 2² + 2³ + ... + 2²⁰²⁴) - (1 + 2 + 2² + 2³)
= 2²⁰²⁴ - 1
b) B = 2²⁰²⁴
B - 1 = 2²⁰²⁴ - 1 = S
B = S + 1
Vậy B > S
a,
\(S=1+2+2^2+...+2^{2023}\)
\(2S=2+2^2+2^3+...+2^{2024}\)
\(\Rightarrow S=2^{2024}-1\)
b.
Do \(2^{2024}-1< 2^{2024}\)
\(\Rightarrow S< B\)
2.
\(H=3+3^2+...+3^{2022}\)
\(\Rightarrow3H=3^2+3^3+...+3^{2023}\)
\(\Rightarrow3H-H=3^{2023}-3\)
\(\Rightarrow2H=3^{2023}-3\)
\(\Rightarrow H=\dfrac{3^{2023}-3}{2}\)
S = 1 + 2 + 22 + ... + 22023
2S = 2 + 22+ 23+ .... + 22024
2S - S = 2 + 22 + 23 + ... + 22024 - (1 + 2 + 22 + 23 +...+ 22023)
S = 2 + 22 + 23 +...+ 22024 - 1 - 2 - 22 - 23 - ... - 22023
S = 22024 - 1
$\dfrac24$
vì $\dfrac24=\dfrac{2 \times 1}{2 \times 2}=\dfrac12$
hai * cuối là 00 vì số nào nhân với 25 thì số hàng chục và đơn vị là 00,còn dấu * thứ 3 là số 7
\(\Leftrightarrow2^2+2^3+2^4+...+2^n=2^{2003}-4\) (1)
Đặt vế trái là VT
\(2VT=2^3+2^4+2^5+...+2^{n+1}\)
\(\Rightarrow VT=2VT-VT=2^{n+1}-2^2\) Thay vào (1)
\(\Rightarrow\left(1\right)\Leftrightarrow2^{n+1}-4=2^{2023}-4\)
\(\Leftrightarrow2^{n+1}=2^{2023}\Rightarrow n+1=2023\Rightarrow n=2022\)