若x+y+z=0 试求(x方-y方-z方)的方-4 y方z方

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若x+y+z=0 试求(x方-y方-z方)的方-4 y方z方
若x+y+z=0 试求(x方-y方-z方)的方-4 y方z方

若x+y+z=0 试求(x方-y方-z方)的方-4 y方z方
因为x+y+z=0
所以x+y=-z x+z=-y
(x²-y²-z²)²-4y²z²
=[(x+y)(x-y)-z²]²-4y²z²
=[-z(x-y)-z²]²-4y²z²
=[-z(x-y+z)]²-4y²z²
=[-z(-y-y)]²-4y²z²
=(2zy)²-4y²z²
=4y²z²-4y²z²
=0
像这样的题,应多考虑将要求的式子.(用我的话就是根据前面给的条件把式子拆来拆去)然后基本会得出结果,希望我的答案能让你明白

(x方-y方-z方)的方-4 y方z方
= (x^2-y^2-z^2+2yz)(x^2-y^2-z^2-2yz)
=[x^2-(y-z)^2][x^2-(y+z)^2]
=[(x+y-z)(x-y+z)][(x+y+z)(x-y-z)]
因为x+y+z=0
所以(x方-y方-z方)的方-4 y方z方 =0

(x^2-y^2-z^2)^2-4y^2x^2
=[(x+y)(x-y)-z^2]^2-4y^2x^2
=[-z(x-y)-z^2]^2-4y^2x^2
=[z(x-y+z)]^2-4y^2x^2
=[z*(-2y)]^2-4y^2x^2
=4y^2x^2-4y^2x^2
=0