x2+y2=(x+y)2+P=(x-y)2+Q,则P=_,Q=_.
问题描述:
x2+y2=(x+y)2+P=(x-y)2+Q,则P=______,Q=______.
答
x2+y2=(x+y)2-2xy=(x-y)2+2xy,故答案为-2xy、2xy.
x2+y2=(x+y)2+P=(x-y)2+Q,则P=______,Q=______.
x2+y2=(x+y)2-2xy=(x-y)2+2xy,故答案为-2xy、2xy.