Posted by AdrianV on .
if f(x)=x^3+5x, then f'(2)=
if f(x)=cos(2x), then f'(pi/4)
derivatives and anti derivatives
please help

MathDerivitives 
bobpursley,
f(x)=x^3+5x
f'=2x^2+5
put in x=2
d (cos2x)/dx=2sin2x
You need to examine why these are causing you difficulty,they are very elementary questions.