Can someone look over my answers for calculus please

Question

anonymous · Answer

attachment

zepdrix · Answer

Just by looking at it, I can tell that (iii) is incorrect.
These intervals are getting smaller and smaller, we should be getting closer and closer to a value. We shouldn't jump from 10 to 22 and back to 11.
Although I guess it's possible ^^

Haha, sec, ill check.

anonymous · Answer

Okay thanks :)

anonymous · Answer

I used the formula f(b)-f(a) / b-a

zepdrix · Answer

sec i gotta slow down -_- making silly mistakes..

anonymous · Answer

when I derive the formula once, would that give me instantaneous value where I can sub in 2 and then get -20 ? for part b? This is all so easy but I forgot the simple formulas :(

zepdrix · Answer

$$\Large\rm f(2.5)=44\cdot2.5-16\cdot2.5^2$$$$\Large\rm f(2.5)=10$$
$$\Large\rm f(2)=44\cdot2-16\cdot2^2$$$$\Large\rm f(2)=24$$

zepdrix · Answer

See how you came up with a bunch of different numbers?
That shouldn't be happening.
You should be heading towards a number, a decimal that get's more and more accurate.

So for part b, it'll just be obvious once we get the correct numbers for a.

zepdrix · Answer

$$\Large\rm \frac{f(2.5)-f(2)}{0.5}=\frac{10-24}{0.5}=-28$$Something like that for (i), yes?

anonymous · Answer

oh ...so I wouldnt use 0.5 ?

anonymous · Answer

I think I read the question wrong then

zepdrix · Answer

No. The wording of the question is a little tricky! :)
Gotta pay attention to what they're asking.

STARTING AT 2,
lasting for a half second,
so ENDING AT 2.5

anonymous · Answer

Oh okay ! Ill try those quesitons again then :) For part b) would it be -20 though? Im pretty sure I did it right, please correct me if Im wrong though

zepdrix · Answer

They didn't really want you to use your derivative shortcuts for part b,
but yes looked like you got it ;) hehe

zepdrix · Answer

So realize that EVERY option in part a should be somewhere AROUND -20.
Maybe a little less, a little more in each case.

But if you come up with a number like positive 4, know that you've made a mistake somewhere.

anonymous · Answer

Alright I think I got it this time

anonymous · Answer

attachment

zepdrix · Answer

I dunno, I don't feel like checking all of those :)
lol

But those numbers look reasonable! They're probably correct ^^

anonymous · Answer

aha okay thank you so much ! :) You were a great help

zepdrix · Answer

See how each number is getting closer and closer to -20 as the interval becomes smaller? Yay team!

anonymous · Answer

aha yes ! :) Thanks !