(x²+y²)²-x²y²=(x²+y²)²-(xy)²=(x²+y²+xy)(x²+y²-xy)=(x+y)²(x-y)²-xy+xy=(x+y)²(x-y)²
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(x²+y²)²-x²y²=(x²+y²)²-(xy)²=(x²+y²+xy)(x²+y²-xy)=(x+y)²(x-y)²-xy+xy=(x+y)²(x-y)²
(x²+y²)²-x²y²
=(x²+y²)²-(xy)²
=(x²+y²+xy)(x²+y²-xy)
=(x+y)²(x-y)²-xy+xy
=(x+y)²(x-y)²
(x²+y²)²-x²y²=(x²+y²)²-(xy)²=(x²+y²+xy)(x²+y²-xy)=(x+y)²(x-y)²-xy+xy=(x+y)²(x-y)²
(x²+y²)²-x²y²
=(x²+y²)²-(xy)² (下面用平方差公式)
=(x²+y²+xy)(x²+y²-xy) (其实到这一步已经可以了,符合因式分解了,因为他是两个多项式的乘积)
=(x+y)²(x-y)²-xy+xy (这一步我知道你是想展开,但是你展开错了,应该是这样的:(a+b)(c+d)=a(c+d)+b(c+d)=ac+ad+bc+bd,你缺少了一些项,所以错了)
=(x+y)²(x-y)² (所以这一步也错了)
最后的答案应该是第二步就可以了!
(x²+y²)²-x²y²
=(x²+y²)²-(xy)²
=(x²+y²+xy)(x²+y²-xy)
到此为至还对,下面算的就没道理了
错了,不可由(x²+y²+xy)(x²+y²-xy) 得到(x+y)²(x-y)²-xy+xy
若此题为因式分解,则(x²+y²+xy)(x²+y²-xy)为最后答案
不对 倒数第二步
应该是((X+Y)^2+XY)((X+Y)^2-XY)
到了第三行就到头了,注意是+xy,不是+2xy
不对。
(x²+y²+xy)(x²+y²-xy) 不等于 (x+y)²(x-y)²-xy+xy
随便举个反例:x=1,y=1时,左边=3,右边=0
(x²+y²)²-x²y²
=x^4 + y^4 + x²y² (x^4表示x的4次方)
(x²+y²)²-x²y²
=(x²+y²)²-(xy)²
=(x²+y²+xy)(x²+y²-xy)
后面错
应该是
. x^3 +y^3......x^3 -y^3
= ---------- * -----...
全部展开
(x²+y²)²-x²y²
=(x²+y²)²-(xy)²
=(x²+y²+xy)(x²+y²-xy)
后面错
应该是
. x^3 +y^3......x^3 -y^3
= ---------- * -----------
. x+y............ x-y
. x^6 -y^6
=------------
. x^2 -y^2
不知道你要化到什么程度...如果是因式分解,到(x²+y²+xy)(x²+y²-xy) 就可以了
收起
不对吧
x²+y²)²-x²y²
=(x²+y²)²-x²y²
=x*x*x*x+y*y*y*y+2x²y²-x²y²
=xxxx+yyyy+x²y²
不对呀!
错