WJEC C2 January 2014 [17/1/14]

I had r, not the value for a


Posted from TSR Mobile

Ah I put the numbers in before re arranging which probably caused me mistakes, i was rushing like mad! Hopefully I'll get some marks for workings!


Posted from TSR Mobile

Do you remember what you had for a?

Yeah I hope so.. I hope they are nice markers! Aha
also all the other grade boundaries are like 58 for an A except the most recent one which is 62 (why did they put it up?? Not fair!) aha

I absolutely hope so too! I really really need a highish A


Posted from TSR Mobile

I had 8, not sure if its right? :s

I think it was similar, if not the same as your value of a but mine was positive :/


Posted from TSR Mobile

Dam, I've just repeated the question and found that positive 2916 seems right..ugh that's a mark lost. Such a stupid mistake!

When substituting r into:

4/r^3 = -108

I didn't put the r within brackets.
I put:

-1/3^3

This came out to equal -2916

Should have put:

(-1/3)^3

This comes to equal 2916.

Well I hope you get what you want! Good Luck!
i need and A overall aswell :/

How did you get to that answer?

Awh thank you! You too you doing c3 on Wednesday ?


Posted from TSR Mobile

I used the sum of an ap formula for n terms and plugged the values of 'a' and 'd' in and came out with an equation 'n^2+8n'. I then did the same for '2n' and came out with '4n^2+16n'. I put the equations together with the sum of 2n equalling 3 times the sum of n. I then solved for n by factorising and ended up with n=0 or n=8.

I used the sum of an ap formula for n terms and plugged the values of 'a' and 'd' in and came out with an equation 'n^2+8n'. I then did the same for '2n' and came out with '4n^2+16n'. I put the equations together with the sum of 2n equalling 3 times the sum of n. I then solved for n by factorising and ended up with n=0 or n=8.