Question

s=1+3+3 mũ 3 +3 mũ 3 +....3 mũ 99

Answer 1

\(S=1+3+3^2+...+3^{99}\)

\(\Rightarrow3S=3+3^2+...+3^{100}\)

\(\Rightarrow3S-S=\left(3+3^2+...+3^{100}\right)-\left(1+3+..+3^{99}\right)\)

\(\Rightarrow2S=3^{100}-1\)

\(\Rightarrow S=\frac{3^{100}-1}{2}\)

Answer 2

S=\(1+3+3^2+3^3+...+3^{99}\)

3S=\(3+3^2+3^3+3^4+...+3^{100}\)

3S-S hay 2S=\(3^{100}-3\)

S=\(\left(3^{100}-3\right):2\)

Hok tốt!!!

Answer 3

thanks

Answer 4

Xin lỗi nha, mình gõ nhầm. Phải là:

3S-S hay 2S=\(\left(3^{100}-1\right)\)

S=\(\left(3^{100}-1\right):2\)

Hk tốt!!!