推 iverson33344:感謝!! 05/20 09:06
※ 引述《iverson33344 (iverson33344)》之銘言：
: 題目如下
: (1+y)^2 -2x^2(1+y^2) +x^4(1-y)^2 =???
: 答案(x-xy+1+y)(x-xy-1-y)(x-1)(x+1)
: 懇求高手幫忙!!!!謝謝!!!
對x^2作判別式把y項當係數得兩根 (1 + y)^2 / (1 - y)^2 and 1
= ((1 - y)^2*x^2 - (1 + y)^2) * (x^2 - 1)
= ((x-xy)^2 - (1+y)^2) * (x-1)(x+1)
= (x-xy-1-y)(x-xy+1+y)(x-1)(x+1)
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※ 編輯: elfkiller 來自: 223.139.77.208 (05/18 03:24)