its derivative is even so since the function was odd its derivative is even so f'(-x)=f'(x)
Suppose that f is an odd function; i.e., f(-x)=-f(x) for all x. Suppose that f'(x) exists. Which of the following must necessarily be equal to f'(-x)?
E) None of the above
i know the answer is A), but I don't know how to solve it. please help!