Question

Tinh tong B=3+3mũ 2+3mũ 3+......+3mũ 100

Tick kkkk

Answer 1

B=3+3²+3³+...+3¹⁰⁰

3B=3.(3+3²+3³+...+3¹⁰⁰)

3B=3²+3³+3⁴+...+3¹⁰⁰+3¹⁰¹

3B-B= 3¹⁰¹-3

Hay 2B=3¹⁰¹-1

B=(3¹⁰¹-1):2

Vậy B=(3¹⁰¹-1):2

Answer 2

Ta có : 3B = 3x(3+3^2+3^3+....+3^99+3^100) = 3^2+3^3+3^4+....+3^100+3^101

Ta lại có 

      3B = 3^2+3^3+3^4+....+3^100+3^101

-

       B  = 3^2+3^3+3^4+....+3^100+3

     2B  = 3^101 - 3

=>   B  = (3^101 - 3)/2

Answer 3

\(\frac{3^{101}-3}{2}\)

Answer 4

3^101-1):2