Question

Tính tổng 

B= 1+3+3²+...+3¹⁰⁰

Answer 1

3B=3+3²+3³+......+3¹⁰¹

3B-B=3¹⁰¹-1

2B=3¹⁰¹-1

\(B=\frac{3^{101}-1}{2}\)

Answer 2

\(B=1+3+3^2+........+3^{100}\)

\(\Rightarrow3B=3+3^2+3^3+.....+3^{101}\)

\(\Rightarrow3B-B=\left(3+3^2+3^3+..+3^{101}\right)-\left(1+3+3^2+...........+3^{100}\right)\)

\(\Rightarrow2B=1-3^{101}\)

\(\Rightarrow B=\frac{1-3^{101}}{2}\)

nếu ai đọc bài này thấy đúng thì k cho mh nhacacs bạn

Answer 3

đặt \(A=1+3+3^2+...+3^{100}\)

ta có : \(3A=3\cdot\left(1+3+3^2+...+3^{100}\right)\)

\(\Rightarrow3A=3+3^2+3^3+...+3^{101}\)

\(\Rightarrow3A=1+3+3^2+3^3+...+3^{101}-1\)

\(\Rightarrow3A=A+3^{101}-1\)

\(2A=3^{101}-1\)

\(\Rightarrow A=\frac{3^{101}-1}{2}\)

vậy \(1+3+3^2+...+3^{100}=\frac{3^{101}-1}{2}\)

Answer 4

B= 1+3+3²+...+3¹⁰⁰

3B=3(1+3+3²+...+3¹⁰⁰)

3B=3.1+3.3+3.3²+...+3.3¹⁰⁰

3B=3+3²+3³+...+3¹⁰¹

3B-B=(3+3²+3³+...+3¹⁰¹)-(1+3+3²+...+3¹⁰⁰)

2B=3¹⁰¹-1

B=\(\frac{3^{101}-1}{2}\)

Answer 5

100 - 100 + 666 - 555 + 111 - 111 + 111 - 222

= 0 + 666 - 555 + 111 - 111 + 111 - 222

= 666 - 555 + 111 - 111 + 111 - 222

= 111 + 111 - 111 + 111 - 222

= 222 - 111 + 111 - 222

= 111 + 111 - 222

= 222 - 222

= 0

Chuc ban hoc tot

Answer 6

Ta có:

B= 1+3+3²+...+3¹⁰⁰

3B=3(1+3+3²+...+3¹⁰⁰)

3B=3.1+3.3+3.3²+...+3.3¹⁰⁰

3B=3+3²+3³+...+3¹⁰¹

3B-B=(3+3²+3³+...+3¹⁰¹)-(1+3+3²+...+3¹⁰⁰)

2B=3¹⁰¹-1

B=3¹⁰¹-1/2

Vậy...