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[QUOTE="Nonamebzja;68253984"]
Original post by Insecure

I see makes sense now


Btw are you taking step aswell?
Original post by Nonamebzja
Btw are you taking step aswell?


He's already at Cambridge.
Original post by Zacken
He's already at Cambridge.


Ohh great!!
Original post by Zacken
He's already at Cambridge.


Btw zacken just came across your step hacks and tricks thread loving it, thanks man:smile:
Reply 704
Insecure


No. I hope we haven't confused you.

A turning point is a turning point if and only if f'(x)=0 (the gradient is 0 at that point) AND f''(x)=/=0 (the sign of the gradient changes).



That would seem to exclude f(x) = x^4 having a turning point at x=0.
(edited 7 years ago)
Original post by RichE
That would seem to exclude f(x) = x^4 having a turning point at x=0.


My. You're right! I tried to make my explanation easy to understand but that seemed to remove the rigour...

A turning point is a point where the derivative changes sign. That should be right :P
Original post by Insecure
My. You're right! I tried to make my explanation easy to understand but that seemed to remove the rigour...

A turning point is a point where the derivative changes sign. That should be right :P


edited
(edited 7 years ago)
Would g(a,b) = s( b-1 , p(a) , p(f(a,m(b)) work for 2015 Q5 part IV?

The idea being that its one less than f(a,b) which = a + b + 1 as g(a,b) has one less iteration due to x = b-1 instead of x=b


(Now changed to replace the b's in g(a,b) with negative b)

@Zacken
(edited 7 years ago)
Reply 708
Original post by Mystery.
if you look at part iii, the f(k)...=-f(2-k)... so it has been reflected in the x-axis
then it also changes from (1+t) to (1-t) essentially this is a reflection the line x=1 because for example if you sub t=0 you get the same function so that is the axis of symmetry
when you reflect or move a graph the area stays the same


Does the 2-k not make a difference because the roots are now different
Original post by Nonamebzja
Btw zacken just came across your step hacks and tricks thread loving it, thanks man:smile:


Can I go through the multiple choice answers for the 2003 paper please? Anyone done it?

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Original post by theaverage
Can I go through the multiple choice answers for the 2003 paper please? Anyone done it?

Posted from TSR Mobile


Hi, I got b, b, c, c, a, c, a, d, a, d.
Can someone check my answers for the 2006 question 7 please?

Spoiler

Thanks :smile:
Reply 712
could someone explain 2013 q3 part 3 and 4 pls.
Original post by Insecure
Hi, I got b, b, c, c, a, c, a, d, a, d.


We wouldn't need to know D or G right?

And how did you get a for I? I got b

Posted from TSR Mobile
Original post by theaverage
We wouldn't need to know D or G right?

And how did you get a for I? I got b

Posted from TSR Mobile


Explain your reasoning.
Original post by Insecure
Explain your reasoning.


I simply did the sum from 1 to 20, because order isn't accounted and you can have 2 of the same.

Not sure if that's right? Yourself?

Posted from TSR Mobile
Original post by theaverage
I simply did the sum from 1 to 20, because order isn't accounted and you can have 2 of the same.

Not sure if that's right? Yourself?

Posted from TSR Mobile


Sorry I meant c) instead of a).

We have 20 choices for our first candy. For each choice of the first candy, we have 20 choices for our second candy. This takes order into account so 20(20)/2=200.
Original post by Insecure
Sorry I meant c) instead of a).

We have 20 choices for our first candy. For each choice of the first candy, we have 20 choices for our second candy. This takes order into account so 20(20)/2=200.


How comes?

If we ignore when they are both the same, we get (20)(19)/2 to discount repeats. Then add the 20 cases when they are both the same = 210?


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Original post by RuairiMorrissey
Would g(a,b) = s( b-1 , p(a) , p(f(a,m(b)) work for 2015 Q5 part IV?

The idea being that its one less than f(a,b) which = a + b + 1 as g(a,b) has one less iteration due to x = b-1 instead of x=b


ya boi is bumping
Original post by Insecure
Sorry I meant c) instead of a).

We have 20 choices for our first candy. For each choice of the first candy, we have 20 choices for our second candy. This takes order into account so 20(20)/2=200.
In the case where you choose the same for both, you don't end up double counting, so dividing the complete total ends up giving the wrong answer.

E.g. with 3 sweet types A, B, C the options including order are:

AA, AB, AC
BA, BB, BC
CA, CB, CC

AA, BB and CC only appear once, it's only the cases where we have 2 different letters that we end up double counting (i.e. AB+BA, AC+CA, BC+CB).

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