(3+1)(x^2+1)(3^4+1)(3^8+1)
(3+1)(x^2+1)(3^4+1)(3^8+1)
(3+1)(x^2+1)(3^4+1)(3^8+1)
(3+1)(x^2+1)(3^4+1)(3^8+1)
(3+1)(3^2+1)(3^4+1)(3^8+1)
=(3-1)(3+1)(3²+1)(3^4+1)(3^8+1)÷(3-1)
=(3²-1)(3²+1)(3^4+1)(3^8+1)÷2
=(3^4-1)(3^4+1)(3^8+1)÷2
=(3^8-1)(3^8+1)÷2
=(3^16-1)÷2
=(3^16-1)/2
(3+1)(3^2+1)(3^4+1)(3^8+1)
=(3-1)(3+1)(3^2+1)(3^4+1)(3^8+1)/(3-1)
=(3^2-1)(3^2+1)(3^4+1)(3^8+1)/(3-1)
=(3^4-1)(3^4+1)(3^8+1)/(3-1)
=(3^8-1)(3^8+1)/(3-1)
=(3^16-1)/2
求什么,求得数?是
(3+1)(x^2+1)(3^4+1)(3^8+1)
还是
(3+1)(3^2+1)(3^4+1)(3^8+1)?
用(3-1)去乘它,然后用平方差公式就可以了,当然最后再把(3-1)给除掉。也就是
原式=(3-1)(3+1)(3^2+1)(3^4+1)(3^8+1)/(3-1)
=(3^2-1)(3^2+1))(3^4+1)(3^8+1)/2
=(3^4-1)(3^4+1)(3^8+1)/2
=(3^8-1)(3^8+1)/2
...
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用(3-1)去乘它,然后用平方差公式就可以了,当然最后再把(3-1)给除掉。也就是
原式=(3-1)(3+1)(3^2+1)(3^4+1)(3^8+1)/(3-1)
=(3^2-1)(3^2+1))(3^4+1)(3^8+1)/2
=(3^4-1)(3^4+1)(3^8+1)/2
=(3^8-1)(3^8+1)/2
=(3^16-1)/2
收起