若x

来源:学生作业帮助网 编辑:作业帮 时间:2024/07/19 14:24:36
若x
x){ѽ&H/AӨ3Ү3ԨЭqu!\JM [T%P(gDUB%cdaPu*``5`)+l*m ^QigrO;tl ]vX

若x
若x

若x
(x^2+y^2)(x-y)-(x^2-y^2)(x+y)
=(x^2+y^2)(x-y)(x-y)(x+y)^2
=(x-y)[(x^2+y^2)-(x+y)^2]
=(x-y)(x^2+y^2-x^2-y^2-2xy)
=-2xy(x-y)
由x0 x-y<0
又-2<0
因此(x^2+y^2)(x-y)-(x^2-y^2)(x+y)>0
(x^2+y^2)(x-y)>(x^2-y^2)(x+y)