一、(x-y)^2[1-(x-y)
二(x+y)^2(1-x-y)
三=(x-y)^2+(x-y)^3=(x-y)^2(1+x-y)
四(x+y)(x-y)(x+y+x-y)=2(x+y)(x-y)x
五=8xyz^2(x+y-z)(3y-z)-32xyz(x-y-z)^2=8xyz[z(x+y-z)(3y-z)-4(x-y-z)^2]
第五个还可以继续分,把x-y-z看成(x-z)-y,前面的也罢x-z提出来,看你要分到哪一步
还可以提别的公因式,你自己试试
(3)设g(x)=[x+f(x)]/xe^x,h(x)=(x^2+x)g'(x)。求证:任意x∈(0,+∞),h(x)<4/3