有理数绝对值的取法.丨a丨等于------(a>=0) ---------(a<0) 丨a丨等于-------(a<=0)
问题描述:
有理数绝对值的取法.丨a丨等于------(a>=0) ---------(a<0) 丨a丨等于-------(a<=0)
答
丨a丨等于a(a>=0)
丨a丨等于-a (a≤0﹚