a)
f ' (x) = [tex] 3x^{2} + 3 = 3( x^{2} +1)[/tex]
b)
f ' (x) = [tex]2 - 4 x^{3} = 2(1-2 x^{3}) [/tex]
c)
f ' (x) = [tex] 1 + \frac{1}{ \sqrt{x} } [/tex]
(2√x ) ' = [tex]2'* \sqrt{x} +2*( \sqrt{x} )'=0* \sqrt{x} +2*(1/2 \sqrt{x} )=0+1/ \sqrt{x} = 1 / \sqrt{x} [/tex]
d)
f ' (x) = [tex]3 x^{2} -cosx-sinx[/tex]
