更新1:
How come you get this x^2-2xy+y^2=(x-y)^2 ?
math question
回答 (3)
2010-02-21 12:37 am
✔ 最佳答案
From equationx^2-2xy+y^2=(x-y)^2
x^2-4xy+4y^2
=x^2-4xy+(2y)^2
=(x-2y)^2
2010-02-21 14:23:17 補充：
x^2-2xy+y^2=(x-y)^2
This is a formula
You should remenber the formula
2010-02-21 3:34 pm
x^2-4xy+4y^2
=x^2-2(x)(2y)+(2y)^2
=(x-2y)^2
x^2-2xy+y^2
=x^2-2(x)(y)+y^2
=(x-y)^2(this is a formula)
=x^2-2(x)(2y)+(2y)^2
=(x-2y)^2
x^2-2xy+y^2
=x^2-2(x)(y)+y^2
=(x-y)^2(this is a formula)
參考: me
2010-02-21 5:00 am
It is an identity.
2010-02-25 18:26:29 補充：
x^2-2xy+y^2=(x-y)^2 is neither an equation nor a formula. It is an identity.
2010-02-25 18:26:29 補充：
x^2-2xy+y^2=(x-y)^2 is neither an equation nor a formula. It is an identity.
收錄日期: 2021-04-28 14:31:44
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100220000051KK01129