实数ab满足ab<0且|a|=6,|b|=7,则a+b的立方根为()
问题描述:
实数ab满足ab<0且|a|=6,|b|=7,则a+b的立方根为()
答
由ab 设 a > 0 b a = 6 b = -7 ==> a+b = -1 ==> 立方根=-1
设 a 0 ==> a=-6 b=7 ==> a+b = 1 ==> 立方根=1
所以 其立方根是1或者-1