Confused about this question (1 Viewer)

[jamesischool]

doing the 2008 2U HSC paper i have absolutely no idea what you're supposed to do with question 9 c) i. and ii.
i have the worked answers in my book but i don't understand why you work it out that way. if you could give a clear explanation that would be much appreciated

 

[Alkanes]

Part one is basically integrating f"(x) from the given equation into f'(x)

I can't see part 2 in ur picture lolz

 

[RishBonjour]

did you integrate second derivative in your book and get ze answer?
I did it that way.

wait, gimme a sec, ill find part 2 in success one :L

lol, second part is integration too.
just integrate and use the conditions given
sub in f(x) = 0 then x = b, then you find C
and then you sub x = 0 to get f(x)

 

[jamesischool]

thanks for the help and yea part 2 got cut off for some reason... still confused a bit but you guys helped

 

[D94]

If you're asked to find the first derivative and you're given the second derivative, then the most direct method would be to integrate the second derivative and substitute given values in to find the constant of integration.

Since it's a "show that", it's sort of obvious whether you got it right or not, but if it just asks you to find the first derivative (like in Applications of Calculus to the Physical World), then once you've integrated the second derivative, you should differentiate it to see if you get the second derivative - if you don't, then you've done something wrong.