(1) y'=4*x^3
(2)y'=6x/(x^2+5)-(6x^3-4x)/(x^2+5)^2
(3)y'=4x+5/2*x^(3/2)
(4)y'=4x^3+2x-1/2*x^(-3/2)
(5)y'=cosx/(1+cosx)+(sinx+sin^2x)/(1+cosx)^2