x(x-y)^3+2x^2(y-x)^2-2xy(x-y)^2其中x=0.5 y=2 过程详细点

显示全部楼层 · 2012-2-15 22:07:02

=x(x-y)^3+2x(x-y)^2(x-y)=x(x-y)^3+2x(x-y)^3=3x(x-y)^3将x和y代入得3*0.5*(0.5-2)^3=-1.5^4=5.0625...

千问 · 2012-2-15 22:07:02

你好！原式= (x-y)2 [x(x-y) +2x2 - 2xy]= (x-y)2 [x2 -xy + 2x2 -2xy]= (x-y)2 (3x2 -3xy)= 3x(x-y)3= 3×0.5 × (0.5 -2)3= 1.5×(-1.5)3...

千问 · 2012-2-15 22:07:02

x(x-y)^3+2x^2(y-x)^2-2xy(x-y)^2=(x2-xy)(x-y)2+2x2(x-y)2-2xy(x-y)2=(x-y)2[x2-xy+2x2-2xy]=(x-y)2[3x2-3xy]=3x(x-y)3=3*...

千问 · 2012-2-15 22:07:02

x(x-y)^3+2x^2(y-x)^2-2xy(x-y)^2=x(x-y)^3+2x^2(x-y)^2-2xy(x-y)^2=x(x-y)^2[(x-y)+2x-2y]=x(x-y)^2(x-y+2x-2y)=x(x-y)^2(3x-3y)=3x(x-y)^3=3*1/2*(1/2-2)^3=3/2*(-3/2)^3=-(3/2)^4=-...