(1)∵y=[x/(1+x)]^5
∴y'=5[x/(1+x)]^4/(1+x)²
=5x^4/(1+x)^6
(2)∵y=(2x+1)^n
∴y'=2n(2x+1)^(n-1)
(3)∵y=sin³(4x+3)
∴y'=4*3sin²(4x+3)*cos(4x+3)
=12sin²(4x+3)*cos(4x+3)
(4)∵y=xcos(x²)
∴y'=cos(x²)-2x²sin(x²)