y'=[2x^2+1]'[-sin(2x^2+1)]=-4x sin(2x^2+1)
y'=[x+(1+x^2)^1/2]'/[x+(1+x^2)^1/2]
=[1+1/2*(1+x^2)^(-1/2)*(1+x^2)']/[x+(1+x^2)^1/2]
=[1+x/(1+x^2)^(1/2)]/[x+(1+x^2)^1/2]
y'=[2x^2+1]'[-sin(2x^2+1)]=-4x sin(2x^2+1)
y'=[x+(1+x^2)^1/2]'/[x+(1+x^2)^1/2]
=[1+1/2*(1+x^2)^(-1/2)*(1+x^2)']/[x+(1+x^2)^1/2]
=[1+x/(1+x^2)^(1/2)]/[x+(1+x^2)^1/2]