Question

if f(x)= x^4 - 4x evaluate lim x->-1 (f(x)-f(-1))/(x+1)
a. -8
b. 0
c. 1
d. 2
e. 4
PLEASE HELP!

Answer 1

it is -8.
By first principle,f'(-1)=lim h->0 (f[-1+h]-f[-1])/h

Answer 2

this is
\[\lim_{x\rightarrow -1}\frac{f(x)-f(-1)}{x+1}\]?

Answer 3

\[f(-1)=5\] so you get
\[\frac{x^4-4x-5}{x+1}=\frac{(x+1) (x^3-x^2+x-5)}{x+1}\]

Answer 4

cancel and replace x b y -1 to get your answer

Answer 5

steps clear?

Answer 6

are you sure thats factored right??