Câu hỏi của Rin & Len Kagamine

Question

A= 3 + 3^<span style="color:rgb(34,34,34);vertical-align:baseline;white-space:now...

Hồ Thu Giang · Accepted Answer

$A=3+3^2+3^3+3^4+...+3^{10}$

=> $A=\left(3+3^2\right)+\left(3^3+3^4\right)+...+\left(3^9+3^{10}\right)$

=> $A=3\left(1+3\right)+3^3\left(1+3\right)+...+3^9\left(1+3\right)$

=> $A=3.4+3^3.4+...+3^9.4$

=> $A=4\left(3+3^3+...+3^9\right)$chia hết cho 4 (Đpcm)

Câu trả lời:

$A=3+3^2+3^3+3^4+...+3^{10}$

=> $A=\left(3+3^2\right)+\left(3^3+3^4\right)+...+\left(3^9+3^{10}\right)$

=> $A=3\left(1+3\right)+3^3\left(1+3\right)+...+3^9\left(1+3\right)$

=> $A=3.4+3^3.4+...+3^9.4$

=> $A=4\left(3+3^3+...+3^9\right)$chia hết cho 4 (Đpcm)

Nguyễn Huy Tú · Answer

A = 3 + 3² + 3³ + ... + 3⁹ + 3¹⁰

=> A = ( 3 + 3² ) + ( 3³ + 3⁴ ) + ... + ( 3⁹ + 3¹⁰ )

=> A = 3( 1 + 3 ) + 3³( 1 + 3 ) + ... + 3⁹( 1 + 3 )

=> A = 3 . 4 + 3³ . 4 + ... + 3⁹ . 4

=> A = ( 3 + 3³ + ... + 3⁹ ) . 4 chia hết cho 4

=> A chia hết cho 4

Vậy...