求(a+b)²-(a-b)²-4ab的值,其中a=2002,b=2001.
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![求(a+b)²-(a-b)²-4ab的值,其中a=2002,b=2001.](/uploads/image/z/3875924-20-4.jpg?t=%E6%B1%82%EF%BC%88a%2Bb%29%26%23178%3B-%EF%BC%88a-b%29%26%23178%3B-4ab%E7%9A%84%E5%80%BC%2C%E5%85%B6%E4%B8%ADa%3D2002%2Cb%3D2001.)
求(a+b)²-(a-b)²-4ab的值,其中a=2002,b=2001.
求(a+b)²-(a-b)²-4ab的值,其中a=2002,b=2001.
求(a+b)²-(a-b)²-4ab的值,其中a=2002,b=2001.
(a+b)²-(a-b)²-4ab
=a²+2ab+b²-a²+2ab-b²-4ab
=0
(a+b)²-(a-b)²-4ab=【(a+b)+(a-b)】*【(a+b)-(a-b)】-4ab=2a*2b-4ab=0
答 这个方程的值为0
=0
A^2 –B^2 =(A+B)(A-B)
(a+b)²-(a-b)²-4ab= (a+b+a-b)(a+b-a+b) -4ab
=2a*2b-4ab =4ab-4ab=0