X1³+X2³怎么算成韦达定理X1+X2,X1X2的形式
问题描述:
X1³+X2³怎么算成韦达定理X1+X2,X1X2的形式
答
X1³+X2³=(x+y)(x^2-xy-y^2)=(x+y)[(x+y)^2-3xy]
答
X1³+X2³
=(x1+x2)(x1^2+x^2-x1x2)
=(x1+x2)[(x1+x2)^2-3x1x2]
答
X1³+X2³
=(x1+x2)(x1²+x1x2+x2²)
=(x1+x2)[(x1²+2x1x2+x2)-x1x2]
=(x1+x2)[(x1+x2)²-x1x2]