化简求值,x+y=2,xy=0.75,求x的3次方y+xy的3次方+2x平方y平方
问题描述:
化简求值,x+y=2,xy=0.75,求x的3次方y+xy的3次方+2x平方y平方
答
=xy(x^2+y^2+2xy) =xy(x+y)^2 =0.75*2^2 =4.75
化简求值,x+y=2,xy=0.75,求x的3次方y+xy的3次方+2x平方y平方
=xy(x^2+y^2+2xy) =xy(x+y)^2 =0.75*2^2 =4.75