Bài 1:

   D     =      5  + 5² + 5³+...+ 5¹⁰⁰

5.D     =             5² + 5³+...+5 ¹⁰⁰ + 5¹⁰¹

5D - D = 5¹⁰¹ - 5

4D       = 5¹⁰¹ - 5

  D      = \(\dfrac{5^{101}-5}{4}\)

Bài 2:

So sánh 

a, 54⁴ = (2.3³)⁴ = 2⁴.3¹²  

    21¹² = (3.7)¹² = 3¹².7¹²

Vì 2⁴ < 7¹² nên 54⁴ < 21¹²

b, 3³⁹ và 11²¹

    3³⁹   =   (3¹³)³

   11²¹ = (11⁷)³

     3¹³ = (3²)⁶.3 = 9⁶.3 < 9⁷ < 11⁷ 

Vậy 3³⁹  < 11²¹

1) \(D=5+5^2+5^3+...+5^{100}\)

\(\Rightarrow D+1=1+5+5^2+5^3+...+5^{100}\)

\(\Rightarrow D+1=\dfrac{5^{100+1}-1}{5-1}\)

\(\Rightarrow D+1=\dfrac{5^{101}-1}{4}\)

\(\Rightarrow D=\dfrac{5^{101}-1}{4}-1=\dfrac{5^{101}-5}{4}=\dfrac{5\left(5^{100}-1\right)}{4}\)

2)

a) \(21^{12}=\left(21^3\right)^4=9261^4>54^4\Rightarrow54^4< 21^{12}\)

b) \(3^{39}< 3^{40}=\left(3^2\right)^{20}=9^{20}< 11^{20}< 11^{21}\)

\(\Rightarrow3^{39}< 11^{21}\)

c) \(201^{60}=\left(201^4\right)^{15}=\text{1632240801}^{15}\)

\(398^{45}=\left(398^3\right)^{15}=\text{63044792}^{15}< \text{1632240801}^{15}\)

\(201^{60}>398^{45}\)

Bạn có thể ghi cho tiết đề bài và bạn muốn làm gì cho bài đó được không?

a/

\(2^{1050}=\left(2^2\right)^{525}=4^{525}< 5^{525}< 5^{540}\)

b/

\(2^{161}>2^{160}=\left(2^4\right)^{40}=16^{40}>13^{40}\)

c/

\(17^{14}>16^{14}=\left(2^4\right)^{14}=2^{56}>2^{55}=\left(2^5\right)^{11}=32^{11}>31^{11}\)

b)Ta có:

 \(3^{99}>3^{93}=\left(3^3\right)^{21}=27^{21}\)

Vì \(27^{21}>11^{21}\) nên \(3^{99}>27^{21}>11^{21}\) hay \(3^{99}>11^{21}\)

a) Ta có:

199²⁰ < 200²⁰ = 200¹⁵.200⁵

2003¹⁵ > 2000¹⁵ = 200¹⁵.10¹⁵ = 200¹⁵.(10³)⁵ = 200¹⁵.1000⁵

Vì 199²⁰ < 200¹⁵.200⁵ < 200¹⁵.1000⁵ < 2003¹⁵

=> 199²⁰ < 2003¹⁵

b) Ta có:

3⁹⁹ = (3³)³³ = 27³³ > 11²¹

=> 3⁹⁹ > 11²¹

a. \(5^{127}=5.5^{126}=5.125^{72}>119^{72}\)

\(\Rightarrow5^{217}>119^{72}\)

b. \(2^{1000}=\left(2^5\right)^{200}=32^{200}\)

\(5^{400}=\left(5^2\right)^{200}=25^{200}\)

\(\Rightarrow2^{1000}>5^{400}\)

c. \(9^{12}=\left(3^2\right)^{12}=3^{24}\)

\(27^7=\left(3^3\right)^7=3^{21}\)

\(\Rightarrow9^{12}>27^7\)

d. \(125^{80}=\left(5^3\right)^{80}=5^{240}\)

\(25^{118}=\left(5^2\right)^{118}=5^{236}\)

\(\Rightarrow125^{80}>25^{118}\)

e. \(5^{40}=\left(5^4\right)^{10}=625^{10}\)

\(\Rightarrow5^{40}>620^{10}\)

f. \(27^{11}=\left(3^3\right)^{11}=3^{33}\)

\(81^8=\left(3^4\right)^8=3^{32}\)

\(\Rightarrow27^{11}>81^8\)

a) a>b vi 1234>999

b) x<y vi 8754<87540

\(a) 3^{200}=(3^2)^{100}=9^{100}\\2^{300}=(2^3)^{100}=8^{100}\)

Vì \(9^{100}>8^{100}\) nên \(3^{200}>2^{300}\)

\(b) 5^{40}=(5^4)^{10}=625^{10}\\3^{50}=(3^5)^{10}=243^{10}\)

Vì \(625^{10}>243^{10}\) nên \(5^{40}>3^{50}\)

#\(Toru\)

a> \(3^{200}\) và \(2^{300}\)

Ta có:\(3^{200}=3^{2.100}=\left(3^2\right)^{100}=9^{100}\)

          \(2^{300}=2^{3.100}=\left(2^3\right)^{100}=8^{100}\)

Vì 9>8 nên \(9^{100}>8^{100}\)

\(\Rightarrow\)\(3^{200}>2^{300}\)

b> \(5^{40}\) và \(3^{50}\)

Ta có:\(5^{40}=5^{4.10}=\left(5^4\right)^{10}=625^{10}\)

         \(3^{50}=3^{5.10}=\left(3^5\right)^{10}=243^{10}\)

Vì 625 > 243 nên \(625^{10}>243^{10}\)

\(\Rightarrow\)\(5^{40}>3^{50}\)

Sửa đề

Bài 1: So sánh\(5^{40}\)và\(4^{50}\)