Câu hỏi của hà anh

Question

(3 +1).( 3 mũ 2 +1).(3 mũ 4 +1).(3 mũ 8 +1)

Trần Thanh Phương · Accepted Answer

$A=\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)$

$2A=\left(3-1\right)\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)$

$2A=\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)$

$2A=\left(3^4-1\right)\left(3^4+1\right)\left(3^8+1\right)$

$2A=\left(3^8-1\right)\left(3^8+1\right)$

$2A=3^{16}-1$

$A=\frac{3^{16}-1}{2}$Câu trả lời: $A=\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)$

$2A=\left(3-1\right)\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)$

$2A=\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)$

$2A=\left(3^4-1\right)\left(3^4+1\right)\left(3^8+1\right)$

$2A=\left(3^8-1\right)\left(3^8+1\right)$

$2A=3^{16}-1$

$A=\frac{3^{16}-1}{2}$

Bài 4: Những hằng đẳng thức đáng nhớ (Tiếp)