Question

A = 1 + 5 + 5^2 + 5^3 +...+ 5^200

Answer 1

A = 1 + 5 + 5^2 + 5^3 +...+ 5^200

=> 5A=5+5^2+...+5^201

=> 5A-A=(5+5^2+...+5^201)-( 1 + 5 + 5^2 + 5^3 +...+ 5^200)

=> 4A = 5^201-1

=> A=\(\frac{5^{201}-1}{4}\)

Answer 2

Sai đề hay sao ấyNguyễn Lê Nhật Đăng

Answer 3

\(A=1+5+5^2+...+5^{200}\)

\(\Rightarrow5A=5+5^2+5^3+...+5^{201}\)

\(\Rightarrow5A-A=\left(5+5^2+5^3+5^{201}\right)-\left(1+5+5^2+...+5^{200}\right)\)

\(\Rightarrow4A=5^{201}-1\)

\(\Rightarrow A=\frac{5^{201}-1}{4}\)

Vậy \(A=\frac{5^{201}-1}{4}\)