整式乘法(2x-y)^2(-2x-y)^2-(4x^2+y^2)(4x^2-y^2)
问题描述:
整式乘法(2x-y)^2(-2x-y)^2-(4x^2+y^2)(4x^2-y^2)
计算(2x-y)^2(-2x-y)^2-(4x^2+y^2)(4x^2-y^2)
其中x=1/29,y=2/29
能简便不?
答
(2x-y)^2(-2x-y)^2-(4x^2+y^2)(4x^2-y^2) =(2x-y)^2(2x+y)^2-(16x^4-y^4)=[(2x-y)(2x+y)]^2-16x^4+y^4=(4x^2-y^2)^2-16x^4+y^4=16x^4-8x^2y^2+y^4-16x^4+y^4=-8x^2y^2+2y^4=-2y^2(4x^2-y^2)其中x=1/29,y=2/29 =-2...