Question

if f(x)= 4+4x-5x^2, find f'(5)

Answer 1

are you allowed to use constant rule,constant multiple rule, power rule?

Answer 2

sum/difference rule?

Answer 3

or do you have to use definition of derivative ?

Answer 4

yeah i believe so

Answer 5

wait to which one sorry

Answer 6

definition or short cuts?

Answer 7

not sure, it doesnt say

Answer 8

well if you guys haven't gone over the short cuts then its the definition
which so far you have this:
\[f'(5)=\lim_{h \rightarrow 0} \frac{f(5+h)-f(5)}{h} \\ f'(5)=\lim_{h \rightarrow 0} \frac{[4-4(5+h)-5(5+h)^2]-[4+4(5)-5(5)^2]}{h}\]

Answer 9

expand and combine like terms

Answer 10

on top

Answer 11

ok let me see what i get

Answer 12

ok i got the answer thank you so much @freckles

Answer 13

that was quick

Answer 14

and i just realized i could of used the short cut, it would have been easier -_-

Answer 15

way easier! :p

Answer 16

yup xp, oh well @freckles but thnx