計算:(2+1)({2}^{2}+1)({2}^{4}+1)({2}^{8}+1)…({2}^{256}+1)

計算:(2+1)({2}^{2}+1)({2}^{4}+1)({2}^{8}+1)…({2}^{256}+1)

答:補上因式(2-1)後重複利用平方差公式
(2+1)({2}^{2}+1)({2}^{4}+1)({2}^{8}+1)…({2}^{256}+1)
=(2-1)(2+1)(2^2+1)(2^4+1)(2^8+1).(2^256+1)
=(2^2-1)(2^2+1)(2^4+1)(2^8+1).(2^256+1)
=(2^4-1)(2^4+1)(2^8+1).(2^256+1)
=(2^8-1)(2^8+1).(2^256+1)
=(2^16-1).(2^256+1)
=2^512 -1