负指数幂的计算:(3x^-1-y)^2-(3x^-1+y)^2
问题描述:
负指数幂的计算:(3x^-1-y)^2-(3x^-1+y)^2
如题,-12y/x
答
x^-1表示1/x,先利用平方差公式得(3x^-1-y+3x^-1+y)(3x^-1-y-3x^-1-y)=(6x^-1)*(-2y)
得-12yx^-1=-12y/x