Methods 3/4 Questions

[vexx]

Need help pleaseeeee:)

Chapter 9K Q4 & Q6

4. If f(3)=−2 and f′(3)=5, find g′(3) if:
a)   g(x)=3x2 −5f(x)   
b)   g(x)= (3x+1)/f(x)

6. Given that f′(x)=√(3x+4) and g(x)=x2−1, find F′(x) if F(x)= f(g(x))

Thanks

[the.watchman]

4 (a)



Do the same for 4(b)



6 Chain Rule

etc.

[vexx]

4 (a)



Do the same for 4(b)



6 Chain Rule

etc.

Thankss!!
Oh Q6 i thought was different because it had a capital F and so was confused heh.

[the.watchman]

No probs!
The statement in the question looks complicated, but it's just saying that it's a composite function

[vexx]

Okay! I have two more questions.

Since they are extended response questions I think it will be silly for me to post the entire thing if you(whoever can answer) already has the Essentials book!

Chapter 10 Extended response questions, p369

Q. 11.   A piece of wire of fixed length, L cm, is bent to....
& Q. 12. A Queensland resort....

Thanks.

[vexx]

buuuumpppp

ps, if you want me to post the question here i can...

[stonecold]

i've spent like an hour on 11 and i have no idea lol.  you somehow have to get theta in terms of r and L.

i'm stuffed now.  i'll take a look at 12 maybe tomoz.  it looks similar to a question which was in the last exercise, so maybe i'll be able to do it haha!

[vexx]

i've spent like an hour on 11 and i have no idea lol.  you somehow have to get theta in terms of r and L.

i'm stuffed now.  i'll take a look at 12 maybe tomoz.  it looks similar to a question which was in the last exercise, so maybe i'll be able to do it haha!

yeah i know i spent ages on 11 too and didn't get it hah!

[m@tty]

What is the question?

[moekamo]

Q. 11.   A piece of wire of fixed length, L cm, is bent to....

We know , we also know that where is in radians

So therefore the total length of wire, and then we can get in terms of r & L:

Plug this into the area of a sector formula to get:

should be able to do the rest of 11 now...

[moekamo]

& Q. 12. A Queensland resort....

again i think once part A is done the rest should be straightfoward...

so from pythag and since the speed he swims at is 1m/s, that is also the time, so

since DC is 75m, PC is (75-x) m and so

it also takes 2 secs to get out of the pool so we add 2 as well



should be able to do the rest now.


also remeber in an exam if they give you the result to show and you cannot show it, you can still use that result in the next parts of the question so skip it and come back and show it later if there is time

[vexx]

^ Thanks a lot moekamo i think i get it! i'll go through it more carefully in the morning when i'm more alert:))

[moekamo]

no worries