C1 Retake Tomorrow!! Final Questions!

I think this is a simple question, I know what to do, but don't actually know why.
In a question, where for example you differentiate a function to get dy/dx as 3x-4sqrtx - why is it when x is 4 (for example), do you only consider the positive root rather than the negative root, and will get 4 as your gradient, rather than 11. Just want to know why...

If you learnt that $\sqrt{4} = \pm 2$, that is categorically untrue and wrong. $\sqrt{4} = + 2$ always. Read this: http://www.thestudentroom.co.uk/showthread.php?t=4066671&p=64637655#post64637655

Also - yes, you need only know the arithmetic sum to n proof.

Thanks so much, sorry to bother, but is there anyway you could try to explain the order of transformation for the problem I gave? (-3f(3x-2)+3?Thanks a lot

You've given a fairly complex transformation there.

I would change around the f(x) --> f(x - 2/3) (translate horizontally) then scale horizontally f(3x -2) --> -3f(3x-2) (scale veritcally) ---> -3f(x3-2) +3 (translate vertically)

You've given a fairly complex transformation there.

I would change around the f(x) --> f(x - 2/3) (translate horizontally) then scale horizontally f(3x -2) --> -3f(3x-2) (scale veritcally) ---> -3f(x3-2) +3 (translate vertically)

Lol do you think they'll give something that complex? wtf...

Right, think I have got it, thanks

They wouldn't, no.

I've just done C1 specimen paper for edexcel, do you think that represents the paper wer going to get in any way and is it supposed to be easier or harder?

I don't know. Your paper could be anything, be ready for anything.

Knowing edexcel they may even throw some c3 and c4 questions in there :P