y'=[1/(根号1+x/1-x)]*(根号1+x/1-x)'
=[1/(根号1+x/1-x)]*(1/2根号1+x/1-x)*[(1+x)/(1-x)]'
=[1/(根号1+x/1-x)]*(1/2根号1+x/1-x)*[(1-x)+(1+x)]/(1-x)²
=[(1-x)/2(1+x)]*{2/(1-x)²]
=1/(1-x)(1+x)
=1/(1-x²)
y'=[1/(根号1+x/1-x)]*(根号1+x/1-x)'
=[1/(根号1+x/1-x)]*(1/2根号1+x/1-x)*[(1+x)/(1-x)]'
=[1/(根号1+x/1-x)]*(1/2根号1+x/1-x)*[(1-x)+(1+x)]/(1-x)²
=[(1-x)/2(1+x)]*{2/(1-x)²]
=1/(1-x)(1+x)
=1/(1-x²)