So sánh : A = 2 mũ 0 + 2 mũ 1 + 2 mũ 2 + 2 mũ 3 + ...... + 2 mũ 2018 và 2 mũ 2019
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a)xét 2A =2+2^2+2^3+.....+2^2019
-A=1+2+2^2+...+2^2018
A=(2^2019)-1 <2^2019
b)theo câu a ta có A+1=2^2019-1+1=2^2019=2^(x+1)
2019=x+1 =>x=2018
\(A=\frac{1}{2^2}+\frac{1}{3^2}+.....+\frac{1}{2018^2}\)
\(< \frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+....+\frac{1}{2017\cdot2018}\)
\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+.....+\frac{1}{2017}-\frac{1}{2018}\)
\(=1-\frac{1}{2018}\)
\(=\frac{2017}{2018}< \frac{3}{4}\)
Ta có :
\(2A=2+2^2+2^3+...+2^{2018}\)
\(\Rightarrow2A-A=\left(2+2^2+2^3+...+2^{2018}\right)-\left(1+2+2^2+...+2^{2017}\right)\)
\(\Rightarrow A=2^{2018}-1< 2^{2018}=B\)
Vậy A<B
Ko ghi đề
\(2A=2+2^2+...+2^{101}\\ 2A-A=2^{101}-1\\ =>A=2^{101}-1\)
Mấy cái khác cg lm như v (b thì 3b)
Nhớ đúng mk nhá
Bài 1:
a) 02002 < 02023
b) 20220 = 20230
c) 549 < 5510
d) ( 4 + 5 )3 > 42 + 52
đ) 92 - 32 > ( 9 - 3 )2
Bài 2:
a) 32 x 43 - 32 + 333
= 9 x 64 - 9 + 333
= 576 - 9 + 333
= 567 + 333
= 900
b) 5 x 43 + 24 x 5 + 410
= 5 x 64 + 24 x 5 + 1
= 5 x ( 64 + 24 ) + 1
= 5 x 88 + 1
= 440 + 1
= 441
c) 23 x 42 + 32 x 5 - 40 x 12023
= 8 x 16 + 9 x 5 - 40 x 1
= 128 + 45 - 40
= 133
Bài 1 :
a) \(0^{2002}=0;0^{2023}=0\Rightarrow0^{2002}=0^{2023}\)
b) \(2022^0=1;2023^0=1\Rightarrow2022^0=2023^0\)
c) \(54^9< 55^9;55^9< 55^{10}\Rightarrow54^9< 55^{10}\)
d) \(\left(4+5\right)^3>\left(4+5\right)^2;\left(4+5\right)^2>4^2+5^2\Rightarrow\left(4+5\right)^3>4^2+5^2\)
đ) \(9^2-3^2=81-9=82;\left(9-3\right)^2=6^2=36\Rightarrow9^2-3^2>\left(9-3\right)^2\)
\(A=2^0+2^1+2^2+2^3+...+2^{2010}\)
\(A=1+2+2^2+2^3+...+2^{2010}\)
\(2A=2+2^2+2^3+...+2^{2011}\)
\(2A-A=\left[2+2^2+2^3+...+2^{2011}\right]-\left[1+2+2^2+2^3+...+2^{2010}\right]\)
\(A=2^{2011}-1\)
Mà \(B=2^{2011}-1\)
=> A = B
Ta có: A=\(2^0+2^1+2^2+2^3+...+2^{2010}\)
2A=\(2^1+2^2+2^3+2^4+...+2^{2011}\)
2A-A hay A=\(2^{2011}-2^0\)
=\(2^{2011}-1\)
Vì \(2^{2011}-1=2^{2011}-1\)
\(\Rightarrow\)A=B
Hok tốt nha!!!
\(A=1+2+2^2+.....+2^{2018}\)
\(\Leftrightarrow2A=2+2^2+....+2^{2018}+2^{2019}\)
\(\Leftrightarrow2A-A=\left(2+2^2+....+2^{2019}\right)-\left(1+2+2^2+....+2^{2018}\right)\)
\(\Leftrightarrow A=2^{2019}-1< 2^{2019}\)
Vậy \(A< 2^{2019}\)