y'=1/(x+√(1+x²))*(x+√(1+x²)'(x+√(1+x²)'=1+1/[2√(1+x²)]*(1+x²)'=1+2x/[2√(1+x²)]=1+x/[√(1+x²)]=[x+√(1+x²)]/√(1+x²)所以y'=1/[x+√(1+x²)]*[x+√(1+...