y=ln[arctan(1/(1+x))]y' = (1/[arctan(1/(1+x))])［arctan(1/(1+x))］'=(1/[arctan(1/(1+x))]).[ (1+x)^2/(1+(1+x)^2)] .(1/(1+x))'=(1/[arctan(1/(1+x))]).[ (1+x)^2/(1+(1+x)^2)] .(-1/(1+x)^2)=(1/[arctan(1/(1+...