S17 JyLps,p]=VVyE-p(p] nh(2)= d d-2 [d-x1-x2 inhiz)-i sindiz)arccomcz)-1/2 In (z+1)/(z-1)) i2) coth (2)=icot am xan=amn SCC (-x)=s PvTsT AT三R 今X arccs 1-为+×m(ba) ]n=b",b0 X axb)n t xere 2) an=a+(n-1)d (x)1 R 纸张加厚 双面书写不港透