f(x)=(1-x/20)^5, f''(40)=?

Question

anonymous · Answer

Take the derivative;
$$f'(x)= d/dx(1-x/20)^5 \implies f'(x) = 5(-1/20)(1-x/20)^4 $$
$$\implies f'(x) = \frac{-1}{4}(1-\frac{x}{20})^4$$
Now plug in 40.

anonymous · Answer

not an option. and it doesn't look right

anonymous · Answer

I didn't plug in 40...This website isn't for you to cheat on your hw in the first place. Just plug in the number 40 for x...the problem is done for you...

anonymous · Answer

no im looking for help with taking the derivative, the derivative is wrong because if i plug in the 40 it doesn't give me the answer listed in the options

anonymous · Answer

ur function is hard to read. is it x/20? or (1-x)/20? clarify. ty

anonymous · Answer

http://www.wolframalpha.com/input/?i=derivative+of+(1-x%2F20)%5E5 Tell me its wrong...

anonymous · Answer

By staring at malevolence19's work, it is correct: There for, ur function is (1-x)/20, not 1-(x/20).

anonymous · Answer

-1/4

anonymous · Answer

(always show work) ppl cant learn if u just give answers == ()