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- bonkissa
- ベストアンサー率50% (1/2)
=x^4-(y^2-z^2)^2-4x^2yz =x^4-(y+z)^2(y-z)^2+((y-z)^2-(y+z)^2)x^2 =x^4-(y+z)^2x^2-(y-z)^2((y+z)^2-x^2) =x^2(x^2-(y+z)^2)+(y-z)^2(x^2-(y+z)^2) =(x^2+(y-z)^2)(x^2^-(y+z)^2) =(x^2+y^2+z^2-2yz)(x-y+z)(x-y-z) point1:(y^2-z^2)^2=(y-z)^2(y+z)^2 point2:-4yz=(y-z)^2-(y+z)^2 以上(^_^;)
- info22_
- ベストアンサー率67% (2650/3922)
x^2=Xとおいてみて F=x^4 - 4 x^2 y z - (y^2 - z^2)^2 =X^2-4yzX-((y+z)(y-z))^2 (y-z)^2-(y+z)^2=-4yz なのでたすきがけ法により F={X+(y-z)^2}{X-(y+z)^2} X=x^2と戻し F=(x^2+y^2+z^2-2yz){x^2-(y+z)^2} 第2項の{ }を因数分解 F=(x^2+y^2+z^2-2yz)(x+y+z)(z-y-z) ←(答) =
x^4 - 4 x^2 y z - (y^2 - z^2)^2 = (x^2 - 2yz)^2 - 4 y^2 z^2 - (y^2 - z^2)^2 = (x^2 - 2yz)^2 - (y^4 + z^4 + 2 y^2 z^2) = (x^2 - 2yz)^2 - (y^2 + z^2)^2 = (x^2 - 2yz - y^2 - z^2)(x^2 - 2yz + y^2 + z^2) = {x^2 - (y + z)^2}(x^2 - 2yz + y^2 + z^2) = (x - y - z)(x + y + z)(x^2 - 2yz + y^2 + z^2)