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AQA FP4 25th May 2016 Discussion Thread

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Original post by Number Nine
yeah me

I swear we had to find detB^-1 lol but others say it was detB
Original post by C0balt
I swear we had to find detB^-1 lol but others say it was detB

No it was definitely det B.
Original post by A Slice of Pi
No it was definitely det B.

Well RIP me
I hope I only lose 1 mark for that
70 hopefully enough for A*
Original post by C0balt
I swear we had to find detB^-1 lol but others say it was detB


Original post by A Slice of Pi
No it was definitely det B.


Original post by C0balt
Well RIP me
I hope I only lose 1 mark for that
70 hopefully enough for A*


STG it was det b^-1

I think I wrote both what det b and det b^-1 equals will that get me the pointages (if assuming I was correct)
For Q6, I found LOIP to be y=-x and when I subbed in a point on that line to xbar,ybar i got the same points.. so shouldn't that be LOIP.
for proving infinite invariant lines, I done ybar=mxbar plus c and manipulated it, factorised all of x,y and m, since c was left alone i said it can be anything, and that was it. I know it wont be full mks, but would it be 2/3??
last question, i said k=1, prism, k=-1 sheaf... and it was 4 mks, how many would i lose???
cheers and sorry for the long post.
was hoping for an a*, as these were probably the only mistakes...
Original post by MahirYuksel
For Q6, I found LOIP to be y=-x and when I subbed in a point on that line to xbar,ybar i got the same points.. so shouldn't that be LOIP.
for proving infinite invariant lines, I done ybar=mxbar plus c and manipulated it, factorised all of x,y and m, since c was left alone i said it can be anything, and that was it. I know it wont be full mks, but would it be 2/3??
last question, i said k=1, prism, k=-1 sheaf... and it was 4 mks, how many would i lose???
cheers and sorry for the long post.
was hoping for an a*, as these were probably the only mistakes...


For LOIP x' = x and y' = y, which gives 3/2x - 2. For k=1 I said prism but also sheaf because I'm an illiterate muppet
Original post by Number Nine
For LOIP x' = x and y' = y, which gives 3/2x - 2. For k=1 I said prism but also sheaf because I'm an illiterate muppet


That doesn't make sense, LOIP crosses via the origin, so how can the intercept be -2? I'm confused.
Original post by MahirYuksel
That doesn't make sense, LOIP crosses via the origin, so how can the intercept be -2? I'm confused.


Not necessarily it's just that the point (x,y) mapped by the transformation to (x,y)
Original post by Number Nine
STG it was det b^-1

I think I wrote both what det b and det b^-1 equals will that get me the pointages (if assuming I was correct)

I hope you're right but oh well, not too confident because detB^-1 would be too easy for a 3 marker of its own you know

I had like half an hour left at the end so I don't even know how I even managed to not realise it was detB not detB^-1 upon checking

Original post by MahirYuksel
For Q6, I found LOIP to be y=-x and when I subbed in a point on that line to xbar,ybar i got the same points.. so shouldn't that be LOIP.
for proving infinite invariant lines, I done ybar=mxbar plus c and manipulated it, factorised all of x,y and m, since c was left alone i said it can be anything, and that was it. I know it wont be full mks, but would it be 2/3??
last question, i said k=1, prism, k=-1 sheaf... and it was 4 mks, how many would i lose???
cheers and sorry for the long post.
was hoping for an a*, as these were probably the only mistakes...

Idk about q6 because I messed up the infinitely many invariant line thing

I don't think you'd get any mark for the last question
K=1 pi1 and pi3 were parallel so you can't form a prism. k=-1 gave inconsistent system for me...?

Original post by Number Nine
For LOIP x' = x and y' = y, which gives 3/2x - 2. For k=1 I said prism but also sheaf because I'm an illiterate muppet

Well thank goodness you got 3/2x-2 lol
Original post by MahirYuksel
That doesn't make sense, LOIP crosses via the origin, so how can the intercept be -2? I'm confused.

You're mixing up with eigenvectors. When eigenvalue is 1 the corresponding eigenvector gives the direction of LOIP through the origin, but LOIP isn't necessarily always through the origin unless the transformation matrix has 1 as an eigenvector
Original post by C0balt
You're mixing up with eigenvectors. When eigenvalue is 1 the corresponding eigenvector gives the direction of LOIP through the origin, but LOIP isn't necessarily always through the origin unless the transformation matrix has 1 as an eigenvector


So would I at least get 2 marks out of the 3 for finding three possible m values after algebraic manipulation?
Original post by MahirYuksel
So would I at least get 2 marks out of the 3 for finding three possible m values after algebraic manipulation?

How did you even get three possible m values? You may get a mark if one of your m values was 3/2.
All you had to do was to say
x=x' or y=y' and rearrange
Both of these would've given y=3/2x-2
Original post by C0balt
How did you even get three possible m values? You may get a mark if one of your m values was 3/2.
All you had to do was to say
x=x' or y=y' and rearrange
Both of these would've given y=3/2x-2


I got set x=x' y=y' and tried to solve. when I set them equal to each other I got 0=0 first time round which was very weird, many people in my class got the same, hence I'm confused. Second attempt at the question after manipulation I arrived at m=-1,3/2,1/2.. I subbed values and y=-x had given me invariant points too on the line. Confused much:angry:, I need this A* so muchhhh......

Boundary predictions for 90UMS??
Original post by MahirYuksel
I got set x=x' y=y' and tried to solve. when I set them equal to each other I got 0=0 first time round which was very weird, many people in my class got the same, hence I'm confused. Second attempt at the question after manipulation I arrived at m=-1,3/2,1/2.. I subbed values and y=-x had given me invariant points too on the line. Confused much:angry:, I need this A* so muchhhh......

Boundary predictions for 90UMS??


I actually got these m values for the infinite number of invariant lines question but I ****ed up that question so lol
When you set them equal to each other you got 0=0 because rearranging x=x' or y=y' in the form y=ax+b they both give the same equation (y=3/2x-2 the LOIP) so they canceled.

I need this A* too after messing up FP3 hard. But unfortunately I don't think the paper was that difficult over all... I'd say boundaries would be similar to last year's
Do you think its alright that I drew a picture for the last question instead of writing a description?
Original post by katie4202
Do you think its alright that I drew a picture for the last question instead of writing a description?


IIRC if you check past mark schemes they say a picture is acceptable (check yourself as im too lazy but 99% sure)
Original post by C0balt
I actually got these m values for the infinite number of invariant lines question but I ****ed up that question so lol
When you set them equal to each other you got 0=0 because rearranging x=x' or y=y' in the form y=ax+b they both give the same equation (y=3/2x-2 the LOIP) so they canceled.

I need this A* too after messing up FP3 hard. But unfortunately I don't think the paper was that difficult over all... I'd say boundaries would be similar to last year's


Surely I should get 1/2 out of 3 for arriving at the two equations giving 0=0.. As I've applied that knowledge. I'm sitting here panicking as if it will change anything, lol at my life xD... I think they'll reduce it to 65... as many people I'm sure has made the same few errors... I guess I have to hope FP2 and D2 go well for me now, as they pick your best 3 A2 modules.
when showing Pi3 doesnt meet pi1 or pi2 i panicked that after finding k values that I got number = 0 then i realised that was meant to be
Original post by MahirYuksel
Surely I should get 1/2 out of 3 for arriving at the two equations giving 0=0.. As I've applied that knowledge. I'm sitting here panicking as if it will change anything, lol at my life xD... I think they'll reduce it to 65... as many people I'm sure has made the same few errors... I guess I have to hope FP2 and D2 go well for me now, as they pick your best 3 A2 modules.


I tend to go for the worst case scenario because I'm pessimistic and also I can prepare for the worst earlier on lol
Well let's just hope that is the case XD

God FP2 is my worst FP module so not counting on that one. Mechanics is my strong fort so M2 and M3 for me... Is D2 any better than D1? If not well my sympathies to you lol
Original post by C0balt
I tend to go for the worst case scenario because I'm pessimistic and also I can prepare for the worst earlier on lol
Well let's just hope that is the case XD

God FP2 is my worst FP module so not counting on that one. Mechanics is my strong fort so M2 and M3 for me... Is D2 any better than D1? If not well my sympathies to you lol


Fp2 is my favorite so I'll rely on that. D2 is very similar to D1 as you must also know algorithms again. Only real difficulty is timing really...

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