# Math Help - The steps to find f''(x)=x^4 - 4x^3

1. ## The steps to find f''(x)=x^4 - 4x^3

i have the answer as f''(x)=12x^2 - 24x and i am not sure how/why i have that

2. Do you mean $f(x)=x^{4}-4x^{3}$? If so:

$f'(x)=4x^{3}-12x^{2}$
$f''(x)=12x^{2}-24x$

3. Originally Posted by Pinkk
Do you mean $f(x)=x^{4}-4x^{3}$? If so:

$f'(x)=4x^{3}-12x^{2}$
$f''(x)=12x^{2}-24x$

thats what i thought. i think my professor made an error. the original is f(x) = x^4 - 4x^3. he said then that f''(x) = 12x^2 - 24x. that made no sense to me...

4. Just take the derivative, then take the derivative of the derivative.