Edexcel A2 C4 Mathematics June 2016 - Official Thread

Everyone else be getting quick replies and I'm just here like sigh. :frown:

Reply 4921

RehanJak98

Original post by nonametosee

Everyone else be getting quick replies and I'm just here like sigh. :frown:

I'd say you get one mark for forming the expression with lambda and one mark for subbing your positive and negative values of lambda to find OE. But if you only found one value for lambda then I'm not sure. I made a similar mistake where i got 2 wrong values for lambda, positive and negative but i still substituted 2 values into the same vector equation.

Reply 4922

Oh no what I meant was I forgot to put a square root around my magnitude for my vector expression for PE which had lambda in it so I got some weird decimal number and so I didn't proceed any further with the question because I just had no confidence in my value for lambda. But what I did have was the diagram for showing 2 position vectors of PE and an expression for PE in terms of lambda and so I couldn't find my OE and an attempt to find magnitude of PE but just without the square root xD

Original post by RehanJak98

I'd say you get one mark for forming the expression with lambda and one mark for subbing your positive and negative values of lambda to find OE. But if you only found one value for lambda then I'm not sure. I made a similar mistake where i got 2 wrong values for lambda, positive and negative but i still substituted 2 values into the same vector equation.

Reply 4923

This was basically all I did (And I had some working left before but that was all wrong but I didn't cancel it out) :frown:

Is it enough to lose only 2-3 marks?

Original post by RehanJak98

I'd say you get one mark for forming the expression with lambda and one mark for subbing your positive and negative values of lambda to find OE. But if you only found one value for lambda then I'm not sure. I made a similar mistake where i got 2 wrong values for lambda, positive and negative but i still substituted 2 values into the same vector equation.

Reply 4924

RehanJak98

usually its 1 mark for forming the correct quadratic expression, then 1 mark for the correct value for lambda, 1 method mark for substituting lambda to find both possible sets of co-ordinates and i'd say 2 accuracy marks for the 2 sets of co-ordinates. Judging by what you've done, I think you can get 1 mark max. with your diagram because it shows some understanding. If you substituted your vale of lambda in the vector equation (even though it was a weird value) you would have got a method mark.

Original post by nonametosee

Oh no what I meant was I forgot to put a square root around my magnitude for my vector expression for PE which had lambda in it so I got some weird decimal number and so I didn't proceed any further with the question because I just had no confidence in my value for lambda. But what I did have was the diagram for showing 2 position vectors of PE and an expression for PE in terms of lambda and so I couldn't find my OE and an attempt to find magnitude of PE but just without the square root xD

Reply 4925

Original post by RehanJak98

usually its 1 mark for forming the correct quadratic expression, then 1 mark for the correct value for lambda, 1 method mark for substituting lambda to find both possible sets of co-ordinates and i'd say 2 accuracy marks for the 2 sets of co-ordinates. Judging by what you've done, I think you can get 1 mark max. with your diagram because it shows some understanding. If you substituted your vale of lambda in the vector equation (even though it was a weird value) you would have got a method mark.

Will the examiner not acknowledge that it may have been a slip in forgetting to put a square root around my magnitude of unit vector PE? If I am actually awarded 1 mark max. that's 71/75. Damn it, I've failed :frown:

No 100 UMS since everyone is saying it was an easy paper.

Reply 4926

somevirtualguy

Original post by RehanJak98

usually its 1 mark for forming the correct quadratic expression, then 1 mark for the correct value for lambda, 1 method mark for substituting lambda to find both possible sets of co-ordinates and i'd say 2 accuracy marks for the 2 sets of co-ordinates. Judging by what you've done, I think you can get 1 mark max. with your diagram because it shows some understanding. If you substituted your vale of lambda in the vector equation (even though it was a weird value) you would have got a method mark.

Oh god, would it be a mark for forming a quadratic? I used a method that didn't involve one, I found the magnitude of the direction vector of the line E and P were on, and equated the magnitudes - something like u5root2=2roo2 to determine that lambda had to be 2/5, and explained by concept it must be positive or negative. Would I get deducted marks for this? I didn't think a quadratic was necessary :/

Reply 4927

hazzam

I think I should get 100 UMS for both C3 and C4. The only thing that I'm worried about is in C3 when they asked for the minimum value of theta and I gave the correct answer but then also wrote the maximum value of theta as well. I labelled both of the values though. Hopefully I won't get penalised.

Reply 4928

somevirtualguy

Original post by somevirtualguy

Oh god, would it be a mark for forming a quadratic? I used a method that didn't involve one, I found the magnitude of the direction vector of the line E and P were on, and equated the magnitudes - something like u5root2=2roo2 to determine that lambda had to be 2/5, and explained by concept it must be positive or negative. Would I get deducted marks for this? I didn't think a quadratic was necessary :/

Anyone?

Reply 4929

maruchan

12

Original post by somevirtualguy

Anyone?

I think there would be many ways to solve this question so you should get all the marks if you answered it correctly. (based on previous C4 markschemes)

Hope that helps :biggrin:

Reply 4930

ImNervous

Hi guys. Unfortunately exams didn't go too well for me this year. But I wanted to get your opinions of the chances of me getting an A.
In core 3 I got around 55
In core 4 I got around 61
My stats 1 is around 64
And I have 257 ums from last year. Any help is greatly appreciated.

Posted from TSR Mobile

Reply 4931

Supermanxxxxxx

5

Original post by ImNervous

Hi guys. Unfortunately exams didn't go too well for me this year. But I wanted to get your opinions of the chances of me getting an A.
In core 3 I got around 55
In core 4 I got around 61
My stats 1 is around 64
And I have 257 ums from last year. Any help is greatly appreciated.

Posted from TSR Mobile

It's gonna be close but I reckon you might have just done it

Posted from TSR Mobile

Reply 4932

ImNervous

Original post by Supermanxxxxxx

It's gonna be close but I reckon you might have just done it

Posted from TSR Mobile

Thanks for your response. It's killing me just thinking about it. Haven't stopped since I came out of that C4 exam knowing I made stupid mistakes costing me marks. I guess I could retake next year. Ugh

Reply 4933

username963570

21

Original post by ImNervous

Thanks for your response. It's killing me just thinking about it. Haven't stopped since I came out of that C4 exam knowing I made stupid mistakes costing me marks. I guess I could retake next year. Ugh

Should be OK. You're looking at mid-B's for C3 and C4 (although the C4 mark will be a high B) but S1 is likely to be between 85-90 UMS (its definitely gonna be sub 60 for an A on that, most likely 57/58) and that combined with 257 UMS for your AS year will put you over the A.

Reply 4934

ImNervous