Question

D = 1+3+3²+3³+3⁴+....+3²⁰²²

tính giá trị biểu thức giú tui với

Answer 1

\(D=1+3+3^2+3^3+3^4+...+3^{2022}\)

\(3D=3.\left(1+3+3^2+3^3+3^4+...+3^{2022}\right)\)

\(3D=3+3^2+3^3+3^4+3^5+...+3^{2023}\)

\(3D-D=\left(3+3^2+3^3+3^4+3^5+...+3^{2023}\right)-\left(1+3+3^2+3^3+3^4+...+3^{2022}\right)\)

\(2D=\left(3^{2023}-1\right)\)

\(D=\left(3^{2023}-1\right):2\)

Answer 2

3D=3+3^2+...+3^2023

=>2D=3^2023-1

=>\(D=\dfrac{3^{2023}-1}{2}\)