(1)y'=2x(3x-2)+3(x^2+3)=6x^2-4x+3x^2+9=9x^2-4x+9
(2)y'=3x^2+cosx/(sinx)^2
(3)f'(x)=-16x+√2
f'(x0)=-16x0+√2=4
x0=-(4-√2)/16