y=0.5(0.5*ln((x+1)/(x-1))+arctanx)
=0.5(0.5*ln(x+1)-0.5ln(x-1)+arctanx)
y'=0.25/(x+1)-0.25/(x-1)+0.5/(1+x^2)还是不大清楚的样子。。。就是先把ln拆开，然后分别求导