What is the derivative of f(x)=-x^3+4x^2 at (-1,5) using the limit definition?

[yourdadonapogostick]

Well, with shortcut here i meant to use the other alternative of the deff. of the derivative,

\lim_{x\rightarrow -1}\frac{f(x)-f(-1)}{x+1} it takes you much faster to the answer.

I'd prefer not to resort to synthetic division.

 

[Precal_Chris]

I'd prefer not to resort to synthetic division.

thats what i did at first...
and i got the -x^3+4x^2-5 to go into (x+1)(-x^2 +5x -5)/(x+1) and so the (x+1) canceled...
but when i told everyone that i got -x^2 +5x -5 for my answer they said that there was no x+1 in the numerator and i had to go through the other equation...
and i just realized if i would have plugged in the -1 for all the x's i would have gotten -11 baack in like post number 15 XD

 

[Precal_Chris]

Well, you will learn this stuff, don't worry about that. I didn't know you were still in high school...lol...

is this for like mostly college people or something?

 

[sutupidmath]

is this for like mostly college people or something?

Well, one usually learns this stuff in calc 1. So, i wrongly guessed...lol..

 

[yourdadonapogostick]

is this for like mostly college people or something?

I learned calculus in high school and I never went to college. I did join the military as a Naval Nuclear Mechanic, though.

 

[Precal_Chris]

oh yeah she said this last six weeks we are going to be doing a lot of calc stuff