这个晚了还在问问题,
两个都对
(1-3x)^(7/3) / 21 - (1-3x)^(1/3) / 12 = (1-3x)^(4/3) ((1-3x)/21 - 1/12)
= (1-3x)^(4/3) * (-1/28 - x/7)
-x/4 * (1-3x)^(4/3) - (1-3x)^(7/3) / 28 = (1-3x)^(4/3) (-x/4 - (1-3x)/28 )
=(1-3x)^(4/3) * (-1/28 - x/7)
因此,两个答案相同.
这个晚了还在问问题,
两个都对
(1-3x)^(7/3) / 21 - (1-3x)^(1/3) / 12 = (1-3x)^(4/3) ((1-3x)/21 - 1/12)
= (1-3x)^(4/3) * (-1/28 - x/7)
-x/4 * (1-3x)^(4/3) - (1-3x)^(7/3) / 28 = (1-3x)^(4/3) (-x/4 - (1-3x)/28 )
=(1-3x)^(4/3) * (-1/28 - x/7)
因此,两个答案相同.