y=(1-x)/x½
y'=(1-x)'x½-(x½)'(1-x)/(x½)²
= -x½-((1-x)/2x½)/x
=-1/2(x-½+x-3/2)
最后答案：负二分之一乘以,X的负二分之一次方加X的负二分之三次方的和