susus
Nov 14, 2010, 12:40 PM
it looks easy but, I do not know what I did wrong:
what is the derivative of f(x) = cosx -1/3(cos^3 x )
the answer is -sin^3 x
while I got -sinx+cos^2 x * sinx !
and also with this :
f(x) = 1/ (x+ sqr(x^2 +1))
what is the derivative of f(x) = cosx -1/3(cos^3 x )
the answer is -sin^3 x
while I got -sinx+cos^2 x * sinx !
and also with this :
f(x) = 1/ (x+ sqr(x^2 +1))